Winter Tire Tread Composition for Wet Braking and Snow Grip
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Solution Overview
Problem
Winter tires face a challenge in achieving high wet braking performance while maintaining good grip on snow and ice, as solutions that enhance wet braking often compromise snow and ice traction.
Innovation Solution
A tire tread with a specific pattern and rubber composition, featuring a longtotal index of 17 or less, comprising a crosslinkable unsaturated chain polymer base with modified styrene-butadiene copolymer rubber, silica filler, hydrocarbon resin, and octyloate, balances wet braking and snow/ice grip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the amount of silica and/or solution stirene-butadiene (sSBR) is increased in the tread rubber composition, then wet braking performance is significantly improved, but grip on snow and ice deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the rubber blend by introducing modified SBR with specific glass transition temperature (-50°C or less) and controlling the ratios of NR, BR, and modified SBR. This parameter optimization allows the tread to achieve both wet braking performance and snow/ice grip without the need for excessive silica or conventional sSBR that would harm winter performance
Solution Approach 2:
The patent creates a composite rubber material system combining natural rubber (NR), polybutadiene rubber (BR), and modified stirene-butadiene copolymer rubber in specific proportions. This composite formulation leverages the complementary properties of each component: NR for softness, BR for low-temperature grip, and modified SBR for wet braking, achieving a balance that individual materials cannot provide
2Reliability
If the tread rubber composition is made softer to improve grip on icy or snowy road surfaces, then grip and handling are improved, but wet braking performance deteriorates
Solution Approach 1:
The patent optimizes the glass transition temperature parameter of the rubber blend by incorporating modified SBR with Tg of -50°C or less, while controlling the overall softness through the NR/BR/modified SBR ratio. This parameter control allows the tread to remain sufficiently soft for winter grip while maintaining the structural integrity needed for wet braking performance
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 tread design and composition significantly improve both wet braking and snow traction performance, ensuring safer winter driving conditions.
Implementation Method 1
a crosslinkable unsaturated chain polymer base comprising from 10 to 50 phr of a modified stirene-butadiene copolymer rubber having a glass-transition temperature (Tg) of −50° C. or less
Implementation Method 2
b) a filler comprising 40 to 100 phr of silica
Implementation Method 3
a crosslinkable unsaturated chain polymer base comprising from 10 to 50 phr of a modified stirene-butadiene copolymer rubber
Data Source
AI summary
The present invention relates to a tread of a tyre having a tread pattern with a longtotal index (As) equal to or less than 17; said tread being characterized in that it is made up of a rubber composition comprising: (a) a crosslinkable unsaturated chain polymer base comprising from 10 to 50 phr of a modified styrene-butadiene copolymer rubber having a glass-transition temperature (Tg), measured by differential scanning calorimetry, of −50° C. or less; (b) a filler comprising 40 to 100 phr of silica; (c) a plasticizer system comprising a hydrocarbon resin and from 8 to 25 phr of octyloleate; and (d) a vulcanization system; said hydrocarbon resin having a softening point of 110° C. or higher, and an average molecular weight comprised between 700 and 1500 g/mol.