Pneumatic Tire Inner Liner Reducing Rolling Resistance
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Solution Overview
Problem
Pneumatic tires face challenges with inner liners that have insufficient vulcanization adhesiveness and non-vulcanization stickiness, leading to air leaks, reduced operation stability, and increased rolling resistance, while existing solutions either complicate the manufacturing process or increase heat generation.
Innovation Solution
A pneumatic tire with an inner liner made of a polymer sheet or laminate, comprising a styrene-isobutylene-styrene triblock copolymer and a rubber component, along with sulfur, which provides both non-vulcanization stickiness and vulcanization adhesiveness, reducing rolling resistance and enhancing operation stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If thermoplastic elastomer is used for inner liner to reduce thickness and weight, then air permeation resistance is improved and weight is reduced, but vulcanization adhesiveness with adjacent rubber layers deteriorates
Solution Approach 1:
The patent uses a composite material system consisting of thermoplastic elastomer (SIBS) combined with butyl rubber and sulfur. The butyl rubber component provides vulcanization adhesiveness through crosslinking reactions with adjacent rubber layers, while the thermoplastic elastomer matrix maintains low weight and high air permeation resistance. This composite approach allows the inner liner to achieve both weight reduction and sufficient adhesiveness simultaneously.
Solution Approach 2:
The patent modifies the chemical composition parameters of the inner liner by incorporating sulfur (0.1-5 parts by mass per 100 parts of polymer component) and butyl rubber (30-70 parts by mass per 100 parts of polymer component) into the thermoplastic elastomer system. These parameter changes enable vulcanization crosslinking reactions that improve adhesiveness without significantly increasing weight or thickness.
2Reliability
If butyl-based rubber is used for inner liner to ensure adequate adhesiveness, then vulcanization adhesiveness is improved, but thickness and weight increase
Solution Approach 1:
Instead of using pure butyl-based rubber which requires greater thickness (0.6-1.0 mm for passenger cars), the patent creates a composite where butyl rubber (30-70 parts per 100 parts polymer) is dispersed within a thermoplastic elastomer matrix. This allows achievement of adequate adhesiveness with reduced overall thickness (0.5-0.7 mm) and weight.
Solution Approach 2:
The patent applies local quality by concentrating the adhesiveness function in the butyl rubber and sulfur components at the interfaces with adjacent layers, while the bulk of the inner liner consists of lightweight thermoplastic elastomer. This localized functional distribution achieves necessary adhesiveness without requiring uniform thickness throughout the entire inner liner.
3Reliability
If nylon film is used for inner liner to improve adhesiveness, then adhesiveness with rubber composition is improved, but manufacturing process complexity increases
Solution Approach 1:
The patent employs a self-service approach where the inner liner material itself (thermoplastic elastomer with butyl rubber and sulfur) provides the necessary adhesiveness through its inherent chemical composition and vulcanization crosslinking capability. This eliminates the need for separate RFL treatment and rubber cement application steps required by nylon film solutions, thereby simplifying the manufacturing process while maintaining adequate adhesiveness.
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 solution achieves superior air isolation performance, improved adhesiveness with adjacent members, reduced rolling resistance, and enhanced operation stability, while simplifying the manufacturing process and minimizing heat generation.
Implementation Method 1
The polymer composition includes sulfur by greater than or equal to 0.1 mass parts and less than or equal to 5 mass parts with respect to the polymer component by 100 mass parts
Implementation Method 2
superior air isolation performance
Data Source
Figure 1
Figure 2~3
AI summary
A pneumatic tire including an inner liner made of a polymer sheet is provided, and the polymer sheet is made of a polymer composition. The polymer composition includes a polymer component of a styrene-isobutylene- styrene triblock copolymer by greater than or equal to 5 mass% and less than or equal to 80 mass%, and a rubber component of at least one kind selected from the group consisting of natural rubber, isoprene rubber, and isobutylene-isoprene rubber by greater than or equal to 20 mass% and less than or equal to 95 mass%. The polymer composition includes sulfur by greater than or equal to 0.1 mass parts and less than or equal to 5 mass parts with respect to the polymer component by 100 mass parts. The polymer sheet has a thickness T1 of 0.6 mm<T1≤4.0 mm.