Tire Sidewall Rubber Composition for Ozone Resistance and Fuel Efficiency
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Solution Overview
Problem
Existing rubber compositions for tire sidewalls face challenges in ozone resistance and fuel efficiency, with a need for improved performance in both areas.
Innovation Solution
A tire sidewall composed of a rubber composition containing an isoprene-based rubber and a branched conjugated diene copolymer with specific ethylene unit content and thickness ratios, enhancing compatibility and reducing strain to prevent cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rubber composition is used for sidewall to improve ozone resistance, then crack prevention is enhanced, but fuel efficiency may be compromised
Solution Approach 1:
The patent changes the chemical composition parameters of the rubber component by specifying a branched conjugated diene copolymer with ethylene unit content of 30-70 mol% and incorporating it at specific proportions (10-50 parts by mass relative to 100 parts by mass of isoprene-based rubber). This parameter optimization achieves both improved ozone resistance and maintained fuel efficiency
Solution Approach 2:
The patent creates a composite rubber system by combining isoprene-based rubber with a specifically designed branched conjugated diene copolymer containing ethylene units and 1,3-diene structural units. This composite material structure provides synergistic effects that simultaneously improve ozone resistance and fuel efficiency
2Use of energy by moving object
If the sidewall rubber composition is optimized for fuel efficiency, then energy consumption is reduced, but ozone resistance may deteriorate
Solution Approach 1:
The patent optimizes the ethylene unit content parameter within the specific range of 30-70 mol% in the branched conjugated diene copolymer. This parameter control ensures the rubber composition achieves both low rolling resistance (improved fuel efficiency) and high ozone resistance through balanced molecular structure
Solution Approach 2:
The patent controls the thickness parameter T of the sidewall and the content Csw of the branched conjugated diene copolymer to satisfy the relationship M×Csw/T³≥0.08, where M is the ethylene unit content. This mathematical relationship optimizes both fuel efficiency and ozone resistance simultaneously
3Reliability
If the sidewall thickness is increased to prevent cracks, then ozone resistance is improved, but rolling resistance increases
Solution Approach 1:
The patent changes the material composition rather than simply increasing thickness. By incorporating the branched conjugated diene copolymer with specific ethylene content (30-70 mol%) and controlling the thickness parameter T to satisfy M×Csw/T³≥0.08, the patent achieves crack resistance without excessive thickness increase, thereby minimizing rolling resistance
Solution Approach 2:
The patent applies the branched conjugated diene copolymer specifically in the sidewall region where ozone exposure is highest, rather than uniformly throughout the entire tire. This localized quality enhancement provides crack resistance where needed while minimizing overall weight and rolling resistance
Data Source
Figure 1
AI summary
Provided is a tire that can improve in overall performance of fuel efficiency and ozone resistance. The tire is a tire comprising a sidewall, wherein the sidewall is composed of a rubber composition comprising a rubber component, wherein the rubber component comprises an isoprene-based rubber and a branched conjugated diene copolymer, wherein the branched conjugated diene copolymer comprises an ethylene unit and a structural unit derived from a 1,3-diene compound expressed by CH2 = CR - CH = CH2 (wherein, R represents a hydrocarbon group having 3 or more carbon atoms), and wherein M is 50 or more, and M×CSW / T3 is greater than 70, where M represents a content, in mol%, of the ethylene unit in the branched conjugated diene copolymer, T represents a thickness, in mm, of a surface rubber layer at a tire maximum width position, and Csw represents a content, in % by mass, of the branched conjugated diene copolymer in the rubber component.