Tire Sidewall Coating Resists Staining and Ozone
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Solution Overview
Problem
Existing tire coatings with colored outer surfaces face issues such as discoloration due to migration of staining agents, poor adhesion, and sensitivity to ozone and stress, particularly when using halogenated rubbers and crosslinking methods.
Innovation Solution
A protective elastomeric coating layer composed of 55-95 phr nitrile rubber and vinyl chloride polymer, 45-5 phr diene or alpha-olefin elastomeric polymer, and 5-80 phr reinforcing filler, optionally with coloring agents, which prevents staining agent migration and provides strong adhesion and resistance to deformation, ozone, and temperature exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If halogenated rubbers are used in barrier layers to prevent staining agent migration, then migration resistance is improved, but adhesion to the tire surface deteriorates
Solution Approach 1:
The patent uses a composite elastomeric composition containing multiple polymer types (halogenated rubber, nitrile rubber, and diene polymer) in specific proportions. This composite approach combines the migration resistance of halogenated rubbers with the adhesion properties of other elastomers, resolving the contradiction between preventing staining agent migration and maintaining adhesion to the tire surface.
2Strength
If crosslinking is used to activate adhesive polymeric materials, then adhesion is improved, but bonding strength deteriorates due to lower bonding strength
Solution Approach 1:
The patent modifies the chemical composition parameters of the elastomeric material by incorporating specific ratios of halogenated rubber, nitrile rubber, and diene polymers, along with reinforcing fillers and adhesion promoters. These parameter changes enable the material to achieve both adhesion and bonding strength without relying solely on crosslinking activation.
3Shape
If colored compositions are applied to tire sidewalls, then aesthetic appearance is improved, but sensitivity to ozone and stress increases causing cracks
Solution Approach 1:
The patent employs a composite elastomeric composition with multiple polymer components (halogenated rubber for ozone resistance, nitrile rubber for stress resistance, and diene polymer for flexibility) combined with reinforcing fillers. This composite structure maintains aesthetic appearance while significantly improving resistance to ozone and stress that would otherwise cause cracking.
4Object-generated harmful factors
If barrier layers are added to prevent staining agent migration, then migration resistance is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple functions into a single elastomeric coating layer. The composition simultaneously provides staining agent migration resistance, adhesion to the tire surface, bonding strength, and resistance to ozone and stress. This consolidation eliminates the need for separate barrier layers, adhesion promoters, and protective coatings, thereby reducing overall structural complexity.
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 coating layer effectively prevents discoloration and cracking, ensuring a stable and aesthetically intact appearance under various stress conditions, while maintaining strong adhesion to the tire surface.
Implementation Method 1
the colored compositions may have discoloration problems due to the migration of staining agents to the visible surface, typically represented by antioxidants, antiozonants and waxes usually present in the elastomeric compositions
Implementation Method 2
difficulties have been encountered in obtaining a good adhesion between the colored compositions and the surface of the vulcanized tire to be coated
Implementation Method 3
the colored compositions have proved to be sensitive to the action of prolonged static and dynamic stresses in the presence of ozone, with the formation of more or less marked cracks
Data Source
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AI summary
The present invention relates to a tire comprising a pair of sidewalls, wherein at least one of said sidewalls is at least partially coated with at least one coating layer, possibly white or colored, obtained by cross-linking of a protective elastomeric composition, comprising: • from 55 to 95 phr, preferably from 60 to 90 phr, of a mixture of a nitrile rubber and a vinyl chloride polymer, • from 45 to 5 phr, preferably from 40 to 10 phr, of at least a diene and/or alpha-olefin elastomeric polymer, • from 5 to 80 phr of at least one reinforcing filler, and • optionally, from 0.1 to 10 phr of at least one coloring agent.