Cap-Base Tread Composition for Low Rolling Resistance Tires
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Solution Overview
Problem
Existing pneumatic tires face challenges in achieving a high balance of fuel efficiency, abrasion resistance, and molding processability, with conventional techniques still falling short in these areas.
Innovation Solution
A pneumatic tire design featuring a tread composed of a cap tread and a base tread, where the cap tread is made from a rubber composition containing 30 to 120 parts by mass of silica with a BET specific surface area of 180 to 280 m^2/g, and a rubber component with 10% to 30% by mass of natural rubber, with a specific mass ratio of cap tread to base tread that satisfies the inequality 150 ≤ C/B × 100 ≤ 900.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silica with high specific surface area is increased to improve abrasion resistance, then the number of bonding sites with polymer increases, but rolling resistance and molding processability deteriorate
Solution Approach 1:
The patent applies parameter changes by precisely controlling the specific surface area of silica within 180-280 m²/g and the mass ratio of cap tread to base tread within 150-900. This optimization ensures sufficient bonding sites for abrasion resistance while preventing excessive rolling resistance, resolving the contradiction between reliability and energy loss.
Solution Approach 2:
The patent implements local quality by creating a two-layer tread structure with different compositions: the cap tread contains silica with high specific surface area (180-280 m²/g) for abrasion resistance, while the base tread has different properties for low rolling resistance. This localized differentiation allows each layer to optimize its function without compromising the other.
2Reliability
If silica content is increased to improve abrasion resistance, then more bonding sites are available, but molding processability deteriorates
Solution Approach 1:
The patent optimizes molding processability by controlling the specific surface area parameter of silica within 180-280 m²/g and the cap/base tread mass ratio within 150-900. These parameter optimizations ensure adequate bonding sites for abrasion resistance while maintaining rubber composition flexibility for proper molding processability.
3Reliability
If cap tread mass ratio is increased to improve abrasion resistance, then more silica is available, but fuel efficiency deteriorates due to weight increase
Solution Approach 1:
The patent resolves the contradiction between abrasion resistance and fuel efficiency by optimizing the cap tread to base tread mass ratio parameter within 150-900 and silica specific surface area within 180-280 m²/g. This optimization ensures sufficient silica content for abrasion resistance while controlling overall tread weight to maintain fuel efficiency.
Solution Approach 2:
The patent uses composite materials by combining silica with specific surface area 180-280 m²/g and natural rubber (10-30% by mass) in the cap tread, creating a composite formulation that achieves high abrasion resistance through optimized material composition rather than simply increasing weight.
Data Source
AI summary
A pneumatic tire of the present invention comprising a tread composed of a cap tread and a base tread can be provided, wherein the cap tread is formed of a rubber composition comprising 30 to 120 parts by mass of silica having 180 to 280 m2/g of a BET specific surface area based on 100 parts by mass of a rubber component comprising 10% by mass or more and less than 30% by mass of a natural rubber, and wherein C and B satisfy the inequality (1): 150≤C/B×100≤900, where C represents a ratio (% by mass) of a mass of the cap tread to a total mass of the tread, and B represents a ratio (% by mass) of a mass of the base tread to the total mass of the tread, the pneumatic tire achieves a high degree of balance of fuel efficiency, abrasion resistance, and molding processability.