Pneumatic Tire Inner Liner Adhesion Low Temperature
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Pneumatic tires face challenges in achieving a balance between maintaining gas barrier properties and bending resistance while minimizing weight, particularly at low temperatures, with existing inner liner materials like butyl-based rubber and ethylene-vinyl alcohol copolymer (EVOH) exhibiting limitations in crack resistance and weight reduction.
Innovation Solution
A pneumatic tire design featuring an inner liner layer composed of a modified ethylene-vinyl alcohol copolymer and a thermoplastic urethane-based elastomer, integrated with a rubbery elastomer and an adhesive layer, ensuring an average peel strength of 6 kN/m or greater at -20°C and 4 kN/m or greater at 23°C, enhancing both gas barrier properties and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the thickness of the inner liner layer is decreased to reduce tire weight, then weight reduction is achieved, but the cord at the inner face tends to be exposed and strength decreases
Solution Approach 1:
The patent uses a composite inner liner structure combining a thermoplastic resin layer (providing gas barrier properties) with a rubbery elastomer layer (providing strength and flexibility). This composite approach allows the inner liner to maintain sufficient strength and protective function while reducing overall thickness and weight compared to conventional single-material inner liners made entirely of butyl-based rubber.
2Reliability
If butyl-based rubber content is increased to improve gas barrier property, then air permeability decreases, but unvulcanized rubber strength decreases and fracture occurs
Solution Approach 1:
The patent divides the inner liner into two distinct functional layers: a thermoplastic resin layer (such as EVOH) that provides the gas barrier function, and a separate rubbery elastomer layer that provides strength and flexibility. This segmentation allows each layer to optimize its specific function without the trade-offs inherent in using high concentrations of butyl-based rubber alone.
3Weight of moving object
If a film of thermoplastic resin is used as inner liner to reduce weight, then weight decreases, but adhesion to rubbery elastomer deteriorates
Solution Approach 1:
The patent introduces an adhesive layer as an intermediary between the thermoplastic resin layer and the rubbery elastomer layer. This adhesive layer facilitates strong bonding between the two dissimilar materials, ensuring that the composite inner liner structure maintains integrity under various conditions including low temperature and dynamic loading.
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 provides excellent average peel strength and bending resistance, maintaining internal pressure and reducing tire weight, effectively addressing the limitations of previous materials in cold and ordinary environments.
Implementation Method 1
an adhesive layer, wherein an average peel strength between a surface of the layer of a single-layered or multi-layered film of a thermoplastic resin and the rubbery elastic layer is 6 kN/m or greater at −20° C.
Implementation Method 2
an ethylene-vinyl alcohol copolymer (hereinafter, referred to as EVOH, occasionally) exhibits an excellent gas barrier property. Since the air permeability of EVOH is one hundredths or smaller of the rubber composition for the inner liner comprising butyl-based rubber
Data Source
AI summary
A pneumatic tire in which the average peel strength between the surface of (A) a layer of a single-layered or multi-layered film of a thermoplastic resin and (B) a rubbery elastic layer, which are used as the inner liner layer, is 6 kN/m or greater at −20° C., i.e., a pneumatic tire exhibiting excellent average peel strength between the surface of layer (A) and layer (B), which are used in combination as the inner liner layer exhibiting excellent gas barrier property and flexibility, at a low temperature and at the room temperature, is provided.