Tyre Inner Liner Composition with Graphite and Chalk
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Solution Overview
Problem
Current rubber compositions for tire inner layers face challenges in achieving optimal air impermeability while maintaining mechanical properties and processability, often requiring high quantities of reinforcing fillers that can degrade these properties.
Innovation Solution
A rubber composition comprising predominantly highly unsaturated diene elastomer, graphite, chalk, and a hydrocarbon plasticizing resin with a glass transition temperature greater than 20°C and softening temperature less than 170°C, which improves gas impermeability and mechanical properties while maintaining good processability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If reinforcing fillers such as carbon black are added to improve impermeability, then gas impermeability is improved, but processability and mechanical properties deteriorate
Solution Approach 1:
The patent introduces a specific plasticizer as an intermediary substance that mediates between the reinforcing fillers (carbon black) and the rubber matrix. This plasticizer enables the fillers to be effectively incorporated while maintaining both processability and impermeability, resolving the contradiction by facilitating the interaction between conflicting components.
Solution Approach 2:
The patent optimizes the quantity of reinforcing fillers and adjusts compositional parameters (including plasticizer content and filler distribution) to achieve the desired balance. By carefully controlling the filler content within specific ranges and modifying other compositional parameters, the patent improves impermeability while preventing excessive degradation of processability and mechanical properties.
2Reliability
If reinforcing fillers such as carbon black are added in large quantities to improve impermeability, then gas impermeability is improved, but mechanical properties deteriorate
Solution Approach 1:
The plasticizer serves as a mediator that protects the rubber matrix from the negative effects of large quantities of reinforcing fillers. It maintains the flexibility and mechanical integrity of the material while allowing high filler content to achieve superior impermeability, thus resolving the contradiction between filler quantity and mechanical strength.
Solution Approach 2:
The patent creates a composite material system comprising rubber, reinforcing fillers (carbon black), and a specific plasticizer. This composite structure allows the beneficial properties of high filler content (improved impermeability) to coexist with maintained mechanical strength, as the plasticizer prevents filler aggregation and maintains matrix continuity.
3Ease of manufacture
If oil-based plasticizers are introduced to improve processability and mechanical properties, then processability and mechanical properties are improved, but gas impermeability deteriorates
Solution Approach 1:
The patent carefully controls the type and quantity of plasticizer used, selecting specific oil-based plasticizers and limiting their content to optimize the balance between processability and impermeability. By adjusting the plasticizer concentration within specific ranges, the patent prevents excessive oil content from creating pathways for gas permeation while maintaining adequate processability.
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 composition achieves enhanced gas impermeability and mechanical properties, such as increased rigidity and reduced permeability, while maintaining equivalent processability to existing solutions, making it suitable for various vehicle types.
Implementation Method 1
a hydrocarbon plasticizing resin whose glass transition temperature, Tg, is greater than 20°C and whose softening temperature is less than 170°C
Implementation Method 2
improves gas impermeability properties compared to the aforementioned solutions
Data Source
AI summary
The present invention concerns a tyre of which the inner liner comprises a rubber composition made at least principally from a highly unsaturated diene elastomer, a reinforcing organic filler, graphite, chalk, and a hydrocarbon plasticising resin of which the vitreous transition temperature, Tg, is higher than 20°C and the softening temperature is lower than 170°C. Using such a composition in the tyre inner liner, including graphite and a non-reinforcing chalk filler, makes it possible to considerably improve the sealing properties relative to a control composition that comprises only graphite and that already offers an excellent performance in this respect, but also relative to a control composition conventionally used in tyre inner liners, while keeping the properties of rigidity and processability as high-level as conventional control compositions.