Low-Cis Tire Tread Compound for Rolling Resistance and Handling
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Solution Overview
Problem
Existing tire compounds face a challenge in balancing improved rolling resistance with maintaining good handling characteristics and low abrasion, as improvements in one property often lead to deterioration in another.
Innovation Solution
A sulfur-crosslinkable rubber compound for tire treads comprising 50 to 100 phr of low-cis butadiene rubber, up to 20 phr of natural polyisoprene, 5 to 50 phr of non-mineral oil plasticizer, and 10 to 300 phr of silica, with specific functionalizations for interaction with fillers, achieves reduced rolling resistance and high stiffness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional rubber compounds use high-cis butadiene rubber or standard polymer blends to improve wear resistance, then abrasion resistance is improved, but rolling resistance increases and handling characteristics deteriorate
Solution Approach 1:
The patent changes the microstructure parameter of butadiene rubber by using low-cis content (less than 90 wt.%, preferably 20-50 wt.%) instead of conventional high-cis content. This parameter change in polymer microstructure fundamentally alters the balance between abrasion resistance and rolling resistance, achieving both improved wear resistance and reduced energy loss simultaneously
Solution Approach 2:
The patent creates a composite rubber compound system combining low-cis butadiene rubber with specific plasticizers (5-50 phr, non-mineral oil), silica (10-300 phr), and optional SSBR (up to 40 phr). This composite formulation synergistically achieves improved abrasion resistance while maintaining low rolling resistance and good handling characteristics
2Ease of operation
If tread compound stiffness is increased to improve handling characteristics, then handling performance is improved, but rolling resistance increases
Solution Approach 1:
The patent modifies the polymer microstructure parameter by using low-cis butadiene rubber, which inherently provides optimal balance between stiffness for handling and flexibility for low rolling resistance. The specific cis content range (20-50 wt.%) is carefully controlled to achieve the desired mechanical properties without excessive energy loss
3Loss of energy
If more silica is added to improve rolling resistance and wet grip, then rolling resistance is reduced, but abrasion resistance may deteriorate
Solution Approach 1:
The patent optimizes the silica content within the range of 10-300 phr and combines it with low-cis butadiene rubber and specific plasticizers. This coordinated parameter optimization ensures that silica reinforcement improves rolling resistance and wet grip while the low-cis polymer matrix maintains excellent abrasion resistance through its unique microstructure
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 compound results in lower rolling resistance and higher stiffness, correlating with improved handling characteristics and reduced abrasion, as demonstrated by reduced loss factor tan δ and high dynamic storage modulus E', respectively.
Implementation Method 1
the specific combination of a solid, solution-polymerized butadiene rubber (BR, polybutadiene) with a cis content of less than 90 wt% with 5 to 50 phr of at least one plasticizer that is not a mineral oil plasticizer, in silica-containing mixtures leads to a reduced loss factor tan δ (10%)
Implementation Method 2
the dynamic storage modulus E' remains high at 8% elongation, as measured by dynamic mechanical analysis at 55 °C according to DIN 53 513. This correlates with high stiffness and, consequently, good handling characteristics in the tire tread
Implementation Method 3
3,3'-bis(triethoxysilylpropyl)tetrasulfide (TESPT) as a silane coupling agent
Data Source
AI summary
The invention relates to a sulfur-crosslinkable rubber compound, in particular for the tread of vehicle pneumatic tires, comprising at least the following components: - 50 to 100 phr (parts by weight, based on 100 parts by weight of the total rubbers in the compound) of at least one solid, solution-polymerized butadiene rubber (BR) with a cis content of less than 90 wt.%, - up to 20 phr of at least one natural polyisoprene (NR), - up to 40 phr of at least one solution-polymerized styrene-butadiene rubber (SSBR), - 5 to 50 phr of at least one plasticizer that is not a mineral oil plasticizer, and - 10 to 300 phr of at least one silica.