Silane-Functionalized EPDM Additives for Tire Tread Traction Balance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current tire tread compositions face challenges in achieving excellent traction and low rolling resistance while maintaining good tread wear, as they often suffer from a trade-off between wet traction and rolling resistance/tread wear.
Innovation Solution
The development of elastomeric compositions incorporating silane functionalized propylene-ethylene-diene terpolymers, which include a silane coupling agent and an antioxidant, to balance wet traction performance and rolling resistance in tire tread applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If miscible resins are added to increase wet traction, then wet traction is improved, but rolling resistance and tread wear increase
Solution Approach 1:
The invention divides the tread composition into miscible and immiscible resin phases. The immiscible resin forms separate domains that provide wet traction enhancement without the penalty of increased rolling resistance associated with miscible resins. This phase separation allows independent optimization of traction and rolling resistance properties.
Solution Approach 2:
The invention uses a composite system combining miscible and immiscible resins with silane functionalized polyolefin additives. The immiscible resin domains act as discrete reinforcing phases that improve wet traction through enhanced hysteresis loss at low temperatures while maintaining low rolling resistance at high temperatures.
2Object-generated harmful factors
If glass transition temperature is raised to improve wet traction, then wet traction is improved, but rolling resistance and tread wear increase
Solution Approach 1:
The invention creates local immiscible resin domains with specific glass transition temperatures optimized for wet traction. These localized phases provide the necessary viscoelastic properties for improved wet braking without requiring a uniform increase in the overall compound's glass transition temperature, thereby avoiding increased tread wear.
Solution Approach 2:
The invention changes the physical and chemical parameters of the resin system by introducing immiscible phases with specific Tg values. The silane functionalized polyolefin additive modifies the interfacial properties and crosslinking density, allowing optimization of wet traction performance independent of the base compound's glass transition temperature.
3Strength
If silane coupling agent is used to improve mechanical properties, then mechanical properties are improved, but product stability decreases due to hydrolysis and self-condensation
Solution Approach 1:
The invention pre-functionalizes the polyolefin with silane groups before compounding. This preliminary functionalization allows the silane to be incorporated into the polymer chain in a controlled manner, reducing the free silane content that would otherwise undergo hydrolysis and self-condensation. The silane is then activated during vulcanization to provide crosslinking and improved mechanical properties.
Solution Approach 2:
The polyolefin acts as an intermediary carrier for the silane functional groups. Instead of adding free silane coupling agent that hydrolyzes easily, the silane is grafted onto the polyolefin chain, which protects it from premature hydrolysis. During processing, the silane is activated and provides the desired coupling and crosslinking effects.
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
These compositions effectively enhance wet traction without increasing rolling resistance and tread wear, by concentrating carbon black and antioxidants in the polyolefin domain to improve abrasion resistance, cure state, and UV stability.
Implementation Method 1
Silane coupling agent such as Bis[3-(triethoxysilyl)propyl]polysulfide, also known as TESPT or Si69, is commonly used as a functional additive that can react with fillers containing silanol groups during mixing.
Implementation Method 2
The drawback of Si69 is its high tendency to undergo hydrolysis and self-condensation reaction to form Si—O—Si linkage, thus affecting the product stability.
Implementation Method 3
The additive can further comprise a curative agent and one or more fillers
Data Source
AI summary
Elastomeric compositions comprising propylene-ethylene-diene terpolymer based polyolefin additives useful in tire tread compositions. The elastomeric compositions comprise 100 phr (parts by weight per hundred parts of total elastomer) diene elastomers; about 0 to about 80 phr of processing oil; 0 to about 80 phr of a hydrocarbon resin; about 60 to about 140 phr of filler; a curative agent; and about 5 to about 30 phr of a silane functionalized propylene-ethylene-diene terpolymer. The silane functionalized propylene-ethylene-diene terpolymer comprises from about 2 wt. % to about 40 wt. % of ethylene and/or C4-C20 α-olefins derived units, from 0.5 to 10 wt % of diene derived units, and a silane coupling agent. The present elastomeric compositions are useful as tire tread compositions for improved tire performance.