Rubber Composition for Tires with Controlled Polyether Structure
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Solution Overview
Problem
Rubber compositions for tires face challenges in balancing processability, crack resistance, ozone resistance, and discoloration resistance, with existing solutions either accelerating cure or causing unwanted discoloration and surface irregularities.
Innovation Solution
A rubber composition with a reduced average content of consecutive polyethylene oxide units in polyether, combined with specific amounts of polybutadiene rubber, natural rubber, and antioxidants, to improve scorch resistance, ozone resistance, and tire appearance while maintaining a good balance between these properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If polyether with high consecutive polyethylene oxide units is used to prevent discoloration, then discoloration resistance is improved, but cure acceleration occurs causing scorch
Solution Approach 1:
The patent changes the structural parameters of polyether by limiting the average content of consecutive polyethylene oxide units to 90% or less, thereby modifying the molecular arrangement to reduce cure acceleration while preserving discoloration protection. This parameter adjustment resolves the contradiction by finding an optimal structural configuration that balances both requirements.
Solution Approach 2:
The patent uses a composite approach by combining polyether with specific rubber components (polybutadiene rubber, natural rubber, polyisoprene rubber) in defined proportions to create a rubber composition where the interactions between components modulate the overall performance, achieving both discoloration resistance and controlled cure characteristics.
2Object-affected harmful factors
If antioxidants and waxes are allowed to bloom to protect rubber from ozone, then ozone resistance is improved, but white and brown discoloration occurs
Solution Approach 1:
The patent modifies the chemical parameters of antioxidants by selecting specific types (6PPD, TMDQ) and controlling their bloom rate through the polyether structure, thereby reducing excessive surface migration that causes discoloration while maintaining sufficient ozone protection through controlled blooming.
Solution Approach 2:
The patent introduces polyether as an intermediary substance that mediates between antioxidants/waxes and the rubber matrix, controlling their migration and bloom rate to prevent excessive surface accumulation and associated discoloration while maintaining their protective function.
3Object-affected harmful factors
If surface irregularities form from bloomed agents, then ozone protection is enhanced, but tire shine is lost and brown discoloration becomes more noticeable
Solution Approach 1:
The patent changes the physical parameters of bloomed substances by controlling the molecular structure of polyether, which regulates the size and distribution of surface irregularities, thereby maintaining crack resistance while minimizing light scattering that reduces tire shine.
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 composition enhances processability, crack resistance, ozone resistance, and discoloration resistance, achieving a balanced tire appearance with reduced acceleration of cure and surface irregularities, resulting in improved tire performance.
Implementation Method 1
by reducing the average content of at least two consecutive polyethylene oxide units in a polyether while maintaining the amount of the polyether in the rubber compound
Implementation Method 2
The antioxidants and petroleum-derived waxes in rubber vulcanizates migrate (bloom) to the rubber surface of e. g. tires, thereby protecting the rubber from ozone
Implementation Method 3
In order to reduce formation and growth of cracks in the presence of ozone, the rubber compositions contain additives, including, for example, antioxidants
Implementation Method 4
the antioxidants degraded by ozone cause brown discoloration
Data Source
AI summary
The present invention aims to provide a rubber composition for tires that can improve processability, crack resistance, ozone resistance, discoloration resistance, and tire appearance while maintaining a good balance between them, and also to provide a pneumatic tire formed from the rubber composition. The present invention relates to a rubber composition for tires, containing: a rubber component; an antioxidant; and polyether (A), the rubber component having a combined content of polybutadiene rubber, natural rubber, and polyisoprene rubber of 80% by mass or more per 100% by mass of the rubber component, the rubber composition containing the antioxidant in an amount of 0.3 to 7.0 parts by mass per 100 parts by mass of the rubber component, the polyether (A) having an average mass content of at least two consecutive polyethylene oxide units of 85% or less of the polyethylene oxide mass content of the polyether (A).