Heat-Expandable Foam Tire Tread for Ice Grip
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Solution Overview
Problem
Existing winter tires with studless treads are not optimized for both snowy and icy conditions, particularly under melting ice conditions, where the tire's grip performance is compromised due to surface water films formed by pressure melting ice.
Innovation Solution
A tire tread composition featuring a base material with a copolymer based on styrene and butadiene units, combined with a heat-expandable covering material containing reinforcing fillers and hydrocarbon plasticizing resin, which provides improved grip on snowy and icy surfaces by forming a foam rubber structure that enhances traction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rigid tread structure is used to enhance traction on snow, then snow grip is improved, but the tread cannot adapt to pressure melting conditions on ice
Solution Approach 1:
The patent applies dynamics by incorporating heat-expandable foam rubber that undergoes thermal transformation during operation. The foam rubber contains blowing agents and expanding agents that activate at elevated temperatures (such as during braking or when contact with melted ice generates heat), causing the material to expand and create micro-roughness. This dynamic adaptation allows the tread to transition from a relatively smooth state to a micro-rough state, enhancing grip on melting ice while maintaining structural integrity for snow traction.
Solution Approach 2:
The patent employs phase transitions through the use of heat-expandable foam rubber that undergoes volumetric expansion when exposed to heat. The blowing agents and expanding agents trapped within the foam structure generate gas bubbles that cause the material to expand and form a micro-rough surface topology. This phase transition from a denser to a more expanded state enables the tread to adapt its surface characteristics in response to thermal conditions, improving versatility across different winter road conditions.
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 tire tread composition significantly improves grip on snowy and melting ice surfaces, offering enhanced traction and performance across a range of winter driving conditions.
Implementation Method 1
the said rubber composition of the covering material is heat-expandable in the tire in the uncured state, in the form of foam rubber in the tire in the cured state
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a cured or uncured tire, the tread of which comprises a plurality of tread pattern features (1) that are formed from a first rubber material, a so-called "base" material (MB), and defined by cut-outs (3, 4). Said tread pattern features include a contact surface (2), for making contact with the road while the tire is rolling, and at least one sidewall (13, 14, 15, 16). On at least one sidewall of all or part of said tread pattern features, the base material is at least partially coated with a layer of a second rubber material, a so-called "coating" material (MR), different from the base material and comprising at least one rubber composition. Said tire is characterized in that said rubber composition of the coating material is heat-expandable in the tire in the uncured state and takes a foam rubber form in the tire in the cured state. Said tire is moreover characterized in that said rubber composition comprises, in the tire in the uncured state as well as the cured state, at least: 50 to 100 phr of a styrene unit and butadiene unit copolymer, the glass transition temperature of which is greater than -40°C; optionally, 0 to 50 phr of another diene elastomer; more than 50 phr of a reinforcing filler; more than 25 phr of a plastifying hydrocarbon resin, the glass transition temperature of which is greater than 20°C; and optionally, 0 to less than 20 phr of a liquid plastifying agent.