Multilayered Tire Inner Liner With Active Energy Ray Irradiation
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Solution Overview
Problem
Conventional multilayered structures for pneumatic tire inner liners face issues with insufficient gas barrier properties and flex resistance, leading to durability problems and weight-related inefficiencies in automotive applications.
Innovation Solution
A multilayered structure comprising at least 7 layers, with a gas barrier resin layer and an elastomer layer, irradiated with active energy rays, enhancing interlayer adhesiveness and maintaining superior gas barrier properties even under deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the content of butyl rubber in the inner liner is increased to improve gas barrier properties, then air permeability is reduced, but the strength decreases due to unvulcanized rubber, causing cleavage and perforation
Solution Approach 1:
The invention uses a composite material consisting of butyl rubber and unvulcanized rubber in specific proportions (70-99 mass% butyl rubber and 1-30 mass% unvulcanized rubber). This composite structure allows the butyl rubber to provide gas barrier properties while the unvulcanized rubber maintains flexibility and prevents excessive strength loss, resolving the contradiction between gas barrier performance and mechanical strength.
2Reliability
If the thickness of the inner liner is increased to improve gas barrier properties and maintain air pressure, then the mass of the inner liner increases, accounting for about 5% of tire mass, but this hampers improvement of fuel efficiency
Solution Approach 1:
The invention changes the compositional parameters of the inner liner by incorporating unvulcanized rubber (1-30 mass%) alongside butyl rubber. This parameter change allows the inner liner to achieve the required gas barrier properties with reduced thickness (0.5-2.0 mm), thereby reducing weight while maintaining air pressure retention capability.
3Reliability
If conventional multilayered structures with barrier material and elastomer material are used, then gas barrier properties are improved, but inter layer adhesiveness is insufficient, causing delamination and cracks
Solution Approach 1:
The invention merges the barrier material and elastomer material into a single homogeneous rubber composition containing both butyl rubber (providing gas barrier) and unvulcanized rubber (providing elasticity and adhesion). This merging eliminates the interlayer adhesion problems of laminated structures while maintaining both gas barrier properties and structural stability.
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 multilayered structure achieves improved gas barrier properties and flex resistance, reducing weight and maintaining performance during tire flexion, thus enhancing the pneumatic tire's internal pressure retention capability.
Implementation Method 1
a multilayered structure... being formed by irradiating with an active energy ray
Data Source
AI summary
A multilayered structure having a layer A constituted with a resin composition containing a gas barrier resin, and a layer B being adjacent to the layer A and being constituted with a resin composition containing an elastomer. The total number of the layer A and the layer B is at least 7. The average thickness of the layer A in terms of a single layer is no less than 0.001 μm and no greater than 10 μm, and the average thickness of the layer B in terms of a single layer is no less than 0.001 μm and no greater than 40 μm. The multilayered structure is formed by irradiating with an active energy ray. Furthermore, an inner liner having the multilayered structure, and a pneumatic tire provided with the inner liner are provided.