Modified Diene Elastomer Reducing Hysteresis in Tire Treads
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Solution Overview
Problem
Current rubber compositions for tire manufacturing face challenges in reducing hysteresis while maintaining creep resistance and raw processing suitability, which is essential for efficient tire performance and production.
Innovation Solution
A modified diene elastomer comprising at least 70% by weight of a linear diene elastomer functionalized with an alkoxysilane group, optionally hydrolyzed, and up to 30% by weight of a star diene elastomer, with a Mooney viscosity between 30 to 80, is used to improve the hysteresis and creep resistance compromise in rubber compositions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If diene copolymers are functionalized with alkoxysilane derivatives to reduce hysteresis, then hysteresis is reduced and abrasion resistance is improved, but the properties remain insufficient for use in tire tread compositions
Solution Approach 1:
The patent combines linear diene copolymers functionalized with alkoxysilane derivatives and star diene copolymers in a composite elastomer system. The linear component (70-90 phr) provides hysteresis reduction through silane-silica interaction, while the star component (10-30 phr) contributes to mechanical strength and processability, creating a composite material that achieves both low hysteresis and sufficient tire tread performance
Solution Approach 2:
The patent optimizes the ratio of linear to star diene copolymer (70:30 to 90:10 by weight) and controls the polymolecularity index (1.2-1.6) to achieve the desired balance between hysteresis reduction and mechanical properties. This parameter optimization enables the elastomer to meet tire tread requirements while maintaining low energy loss
2Loss of energy
If functionalization with alkoxysilane functions is combined with thiol functions to reduce hysteresis by decreasing energy dissipation related to free chain ends, then hysteresis is reduced, but elastomer creep resistance may be compromised
Solution Approach 1:
The patent introduces specific functional groups (thiol, isocyanate, imine, cyano, carboxylate, epoxide, or phosphine) at the chain ends of the diene copolymer via alkoxysilane functionalization. These localized functional groups interact with reinforcing fillers to reduce hysteresis, while the bulk polymer structure maintains its creep resistance properties
Solution Approach 2:
The patent creates a composite system where functionalized linear diene copolymers (providing low hysteresis) are combined with star diene copolymers (providing structural stability). This composite approach allows the functional groups to reduce energy dissipation while the star polymer network maintains creep resistance
3Loss of energy
If the polymolecularity index is reduced to improve hysteresis properties, then energy dissipation is reduced, but raw implementation and manufacturing may be affected
Solution Approach 1:
The patent optimizes the polymolecularity index to a specific range (1.2-1.6) through controlled polymerization processes. This parameter optimization reduces hysteresis while maintaining adequate raw implementation properties for manufacturing. The Mooney viscosity is controlled (30-80) to ensure 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 modified diene elastomer enhances the raw processing and hysteresis compromise of rubber compositions, maintaining intact creep resistance, thus improving tire performance and manufacturing efficiency.
Implementation Method 1
functionalized predominantly at the chain end by an alkoxysilane group, optionally partially or totally hydrolyzed, carrying another function capable of interacting with a reinforcing filler
Implementation Method 2
an alkoxysilane group, optionally partially or totally hydrolyzed to silanol
Data Source
AI summary
The invention relates to a modified diene elastomer comprising, relative to the total weight of the modified diene elastomer: a) at least 70 wt.-% of a linear diene elastomer functionalised mainly at one chain end by an alkoxysilane group, optionally partially or fully hydrolysed to silanol, the alkoxysilane group bearing another function that can interact with a reinforcing filler selected from among isocyanates, imines, cyano compounds, thiols, carboxylates, epoxides, and primary and secondary phosphines, the alkoxysilane group being connected to the diene elastomer by means of the silicon atom, said functionalised diene elastomer having a pre-functionalisation polydispersity index of less than or equal to 1.6; and b) more than 0 and up to 30 wt.-% of a star-shaped diene elastomer having a pre-star-formation polydispersity index of less than or equal to 1.6, the mooney viscosity of the modified diene elastomer varying between 30 and 80.