Tire Tread Rubber Composition for Low Temperature and Wet Traction
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Solution Overview
Problem
Tire tread rubber compositions face challenges in balancing wet traction and low-temperature performance, as high Tg elastomers can result in stiff cured rubber, compromising cold weather capabilities while maintaining traction.
Innovation Solution
A rubber composition combining high Tg styrene/butadiene elastomers extended with triglyceride vegetable oil, lower Tg cis 1,4-polybutadiene rubber, and pre-hydrophobated precipitated silica, along with a traction resin, to reduce cured stiffness and enhance cold weather performance without detracting from wet traction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high Tg styrene/butadiene elastomers are used to improve wet traction, then wet traction is improved, but cured stiffness increases and cold weather performance deteriorates
Solution Approach 1:
The patent applies parameter changes by extending the high Tg S-SBR with triglyceride vegetable oil, which modifies the rubber composition's physical properties. This extension process changes the molecular structure and reduces the storage modulus at low temperatures, thereby improving cold weather performance while preserving wet traction capabilities through the high Tg elastomer content
Solution Approach 2:
The patent uses composite materials by combining high Tg S-SBR, lower Tg E-SBR, and low Tg cis 1,4-polybutadiene in specific proportions. This multi-component composite approach allows the tread to exhibit both high wet traction (from high Tg S-SBR) and low cured stiffness (from lower Tg elastomers), resolving the contradiction between wet traction and cold weather performance
2Reliability
If high Tg styrene/butadiene elastomers are used to improve wet traction, then wet traction is improved, but cured stiffness increases
Solution Approach 1:
The patent applies parameter changes by extending the high Tg S-SBR with triglyceride vegetable oil, which modifies the rubber composition's physical properties. This extension process changes the molecular structure and reduces the storage modulus at low temperatures, thereby improving cold weather performance while preserving wet traction capabilities through the high Tg elastomer content
Solution Approach 2:
The patent uses composite materials by combining high Tg S-SBR, lower Tg E-SBR, and low Tg cis 1,4-polybutadiene in specific proportions. This multi-component composite approach allows the tread to exhibit both high wet traction (from high Tg S-SBR) and low cured stiffness (from lower Tg elastomers), resolving the contradiction between wet traction and cold weather performance
3Ease of manufacture
If petroleum based rubber processing oil is added to reduce uncured viscosity, then processing conditions are improved, but cured stiffness increases and cold weather performance deteriorates
Solution Approach 1:
The patent replaces expensive petroleum-based processing oil with triglyceride vegetable oil, which is applied in a controlled amount (5-20 phr) to extend the high Tg S-SBR. This substitution provides both processing benefits and improved cold weather performance, as the vegetable oil extender reduces cured stiffness without the harmful effects of petroleum-based oils
Solution Approach 2:
The patent applies parameter changes by using triglyceride vegetable oil extension of high Tg S-SBR, which modifies the rubber composition's physical properties. This extension process changes the molecular structure and reduces the storage modulus at low temperatures, thereby improving cold weather performance while maintaining good processing characteristics
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 solution effectively improves low-temperature traction and maintains wet traction capabilities, as demonstrated by reduced stiffness at -20°C and comparable hysteresis, indicating improved rolling resistance and snow traction.
Implementation Method 1
the high Tg S-SBR is extended with from about 10 to about 38 parts by weight per 100 parts of said high Tg S-SBR of triglyceride vegetable oil
Implementation Method 2
about 50 to about 250, alternately from about 75 to about 175, phr of rubber reinforcing filler comprised of precipitated silica (amorphous synthetic precipitated silica) and rubber reinforcing carbon black
Implementation Method 3
the E-SBR has a Tg which lower than the Tg of the S-SBR, to beneficially promote lowering the stiffness of the cured rubber composition at about −20° C. by compensating for the presence of the higher Tg S-SBR
Implementation Method 4
comparable hysteresis, indicating improved rolling resistance and snow traction
Data Source
AI summary
This invention relates to a tire with tread for promoting a combination of cold weather service at low temperatures and wet traction. The tread is of a rubber composition containing cis 1,4-polybutadiene and dual styrene/butadiene elastomers with reinforcing filler comprised of pre-hydrophobated precipitated silica and rubber reinforcing carbon black. The tread rubber composition may contain triglyceride vegetable oil such as soybean oil.