Tire Sidewall Composition for Ozone Protection Without Staining
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Solution Overview
Problem
Conventional rubber compositions for vehicle tires are prone to surface defects and color alteration due to ozone exposure, leading to stains and cracks, which is particularly problematic for tires with decorative elements or colored sidewalls, as existing protective systems like antioxidants and waxes can cause aesthetic issues.
Innovation Solution
A tire sidewall composition using a phenolic antioxidant in amounts equal to or greater than 3 phr, substantially free of polymeric static protective agents, combined with cyclic-acetal or enol-ether antioxidants, provides effective ozone protection without the aesthetic drawbacks of traditional systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional antioxidants and waxes are used to protect sidewalls from ozone, then protection against ozone-induced cracks is improved, but aesthetic appearance deteriorates due to staining and color alteration
Solution Approach 1:
The patent changes the chemical parameters of the protective system by using high amounts of phenolic antioxidants (≥3 phr) combined with cyclic-acetal or enol-ether antioxidants, replacing the conventional antioxidant-wax system. This parameter change maintains ozone protection while eliminating the staining and color alteration problems associated with traditional additives migrating to the sidewall surface.
Solution Approach 2:
The patent employs a composite antioxidant system combining phenolic antioxidants with cyclic-acetal or enol-ether antioxidants in specific proportions. This composite approach provides synergistic protection against ozone while preventing the aesthetic degradation caused by individual conventional additives, achieving both protective and cosmetic goals.
2Shape
If high amounts of phenolic antioxidants are used without polymeric static protective agents, then aesthetic appearance is maintained, but protection against ozone may be insufficient
Solution Approach 1:
The patent optimizes the concentration parameters of phenolic antioxidants to ≥3 phr, which is sufficiently high to provide both aesthetic benefits and adequate ozone protection. This parameter optimization eliminates the need for polymeric static protective agents while maintaining reliable protection, resolving the apparent contradiction between appearance and protection efficacy.
Solution Approach 2:
The patent creates a composite protective system using phenolic antioxidants in combination with cyclic-acetal or enol-ether antioxidants. This composite material provides enhanced and balanced protection, achieving both aesthetic appearance maintenance and sufficient ozone resistance without requiring additional polymeric agents.
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
This solution effectively reduces ozone-induced staining and color alteration while maintaining good static and dynamic protection, ensuring the tire's appearance remains intact, even with decorative elements, by using high amounts of phenolic antioxidants without the need for waxes or other polymeric agents.
Implementation Method 1
the elastomeric composition is sensitive to the action of atmospheric agents, in particular to oxidation
Implementation Method 2
the antioxidants tend to migrate slowly so as to provide a long lasting protection
Data Source
AI summary
The present invention relates to a tyre for vehicle wheels comprising at least one external structural element comprising at least one external structural element comprising a crosslinked elastomeric material obtained by crosslinking a crosslinkable elastomeric composition comprising (i) at least one diene elastomeric polymer, and (ii) a system for protection against ozone substantially free of polymeric static protective agents which essentially consists of at least one phenolic antioxidant in an amount substantially equal to or higher than 3 phr.