Silane Rubber Composition With Secondary Network for Low Rolling Resistance
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Solution Overview
Problem
There is a need for rubber compositions that achieve an improved balance of low hysteretic properties (low rolling resistance), wear resistance, and traction (handling) properties, particularly in tire applications.
Innovation Solution
The use of a hydrolyzable alkoxymethylamino-functional silane as an additive in rubber compositions, which forms a secondary polymer network when combined with a reinforcing filler like silica, improving the tire's performance characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If carbon black filler is used to enhance wear resistance and tear resistance, then wear properties are improved, but rolling resistance increases and fuel efficiency decreases
Solution Approach 1:
The patent changes the chemical composition parameters of the filler system by introducing silica combined with specific silane coupling agents (alkyltrialkoxysilanes with 3-8 carbon atoms) to replace carbon black. This parameter change transforms the filler's interaction with rubber polymers, reducing hysteresis losses while maintaining wear resistance through optimized silane-rubber crosslinking density.
Solution Approach 2:
The patent creates a composite filler system combining silica particles with organosilane coupling agents that form a hybrid structure. The silane-modified silica composite provides both the reinforcement needed for wear resistance and the low hysteresis characteristics required for reduced rolling resistance, effectively merging the benefits of both filler types while eliminating their individual drawbacks.
2Loss of energy
If silica filler is used to reduce rolling resistance, then energy efficiency is improved, but wear resistance and traction properties deteriorate
Solution Approach 1:
The patent introduces organosilane coupling agents as intermediary substances that mediate the interaction between silica filler and rubber polymers. These silane intermediaries form covalent bonds with both the silica surface and rubber chains, creating an effective stress transfer mechanism that enables silica to provide reinforcement for wear resistance while maintaining its inherent low hysteresis properties for reduced rolling resistance.
Solution Approach 2:
The patent modifies the surface chemistry parameters of silica by grafting organosilane molecules onto the silica surface. This parameter change transforms inert silica into chemically active filler that can form crosslinked networks with rubber, thereby enhancing wear resistance without compromising the low rolling resistance benefit of silica's inherent structure.
3Strength
If silane coupling agents are used to chemically couple rubber with filler, then reinforcement is improved, but tradeoffs in rolling resistance, wear and traction properties occur
Solution Approach 1:
The patent optimizes the molecular structure parameters of silane coupling agents by selecting specific alkyl chain lengths (3-8 carbons) and alkoxide groups, which controls the crosslinking density and network topology. This parameter optimization achieves sufficient reinforcement for wear resistance while preventing excessive crosslinking that would increase hysteresis and worsen rolling resistance, thereby maintaining performance balance.
Solution Approach 2:
The patent applies partial crosslinking through controlled silane coupling rather than complete crosslinking. By using sub-stoichiometric amounts of silane coupling agent and controlling cure conditions, the patent achieves adequate reinforcement for wear resistance while leaving sufficient polymer chain mobility to maintain low hysteresis and good traction properties, avoiding the performance tradeoffs of excessive crosslinking.
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 described rubber compositions exhibit enhanced wear resistance and reduced rolling resistance, maintaining traction while improving the overall performance of tires, especially in heavy vehicle and truck tire applications.
Implementation Method 1
the silane containing a functional group forms silanols by reacting with water or water bound to the reinforcing filler
Implementation Method 2
said silanols react with the reinforcing filler to form a plurality of covalent chemical bonds with the filler
Data Source
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AI summary
A silane based additive, rubber formulations including the additive and tires having tread portions made with the additive, together with methods of forming those products, are provided. Uncured rubber formulations in accordance with preferred embodiments of the invention comprise (1) a rubbery primary polymer or polymer blend, such as natural rubber and/or synthetic rubber; (2) reinforcing silica filler; (3) a network forming monomer or polymer, especially a thermosetting network forming moiety, for forming a secondary polymeric network; and (4) a silane containing one or more moieties of the aforementioned network forming polymer. In particular networks which can be generated in-situ are preferred. The cured rubber formulation should comprise the silica, having the secondary polymer network coupled thereto, within the rubber matrix, and not directly to the rubber chains via sulfidic linkages.