Self-Sealing Tire Composition Manufacturing Process
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Solution Overview
Problem
Existing self-sealing compositions for tires face challenges in manufacturing due to high hydrocarbon resin content affecting hysteresis and rolling resistance, and the use of liquid elastomers leading to composition creep at high temperatures, while reducing liquid elastomer content results in cohesion issues and sticking on tools.
Innovation Solution
A process involving the manufacture of a masterbatch with a diene elastomer and hydrocarbon resin above 30 phr, followed by incorporation of a crosslinking system and a liquid plasticizer with a glass transition temperature below -20°C, at controlled temperatures to produce a self-sealing composition with high hydrocarbon resin content without excessive liquid plasticizer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high content of hydrocarbon resin (>100 phr) is used in self-sealing composition, then self-sealing effectiveness is improved, but hysteresis increases and rolling resistance worsens
Solution Approach 1:
The patent changes the physical state parameter of the elastomer from solid to liquid (depolymerized natural rubber with molecular weight 1000-100,000), which fundamentally alters how the resin interacts with the elastomeric matrix. This parameter change allows the high resin content to achieve self-sealing without the same negative hysteresis effects that would occur with conventional solid elastomers.
2Ease of operation
If large amount of liquid elastomer is used to improve fluidity, then composition fluidity is improved, but composition creeps at high temperature (>60°C)
Solution Approach 1:
The patent changes the molecular weight parameter of the liquid elastomer to a specific range (1000-100,000) and uses it in combination with high resin content. This creates a composition that maintains adequate fluidity for self-sealing while the resin network provides dimensional stability at high temperatures, preventing excessive creeping.
3Stability of the object's composition
If liquid elastomer content is reduced or eliminated to prevent creeping, then dimensional stability at high temperature is improved, but composition lacks cohesion and sticks to compounding tools
Solution Approach 1:
The patent creates a composite material system combining depolymerized natural rubber (liquid elastomer) with high content hydrocarbon resin. The resin acts as both a tackifier and a reinforcing phase, providing cohesion to the composition while allowing reduced liquid elastomer content. This composite approach maintains dimensional stability without excessive sticking to tools.
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 process enables the rapid and cost-effective production of a self-sealing composition that maintains cohesion and prevents sticking, while maintaining puncture resistance and flexibility over a wide temperature range, effectively sealing tire punctures without significant rolling resistance penalty.
Implementation Method 1
a liquid plasticizer having a glass transition temperature below -20°C is furthermore incorporated in an amount of less than 60 phr into said masterbatch or into said composition
Implementation Method 2
then at least one crosslinking system is incorporated into the masterbatch thus prepared, by compounding everything, in the same mixer or in a different mixer
Data Source
AI summary
Process for manufacturing a self-sealing elastomer composition, wherein the process comprises the following steps: firstly a masterbatch comprising at least one diene elastomer and a thermoplastic plasticizing hydrocarbon resin with a content greater than 30 phr is manufactured by compounding these various components in a mixer at a temperature or up to a temperature called the “hot compounding temperature” which is above the softening point of the hydrocarbon resin; and then at least one crosslinking system is incorporated into the masterbatch thus prepared, by compounding everything, in the same mixer or in a different mixer, at a temperature or up to a maximum temperature which is kept below 100° C., in order to obtain said self-sealing composition, and wherein at least one liquid plasticizer having a glass transition temperature (Tg) below −20° C. is furthermore incorporated in an amount of less than 60 phr into said masterbatch or into said composition.