Thermoplastic Laminate Inner Liner for Low Air Permeability Tires
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Solution Overview
Problem
Current materials for the inner liner of pneumatic tires lack a balance between gas barrier properties and flexibility, leading to increased weight and rolling resistance due to the use of halogenated butyl rubber and other materials, which also suffer from adhesion and moisture resistance issues.
Innovation Solution
A laminate composed of a thermoplastic resin with a low air permeation coefficient and a thermoplastic polymer with specific melt viscosity and Young's modulus, laminated together to create a layer with an air permeation coefficient of 20×10−12 cc·cm/cm2·sec·cmHg or less, providing both gas barrier and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If halogenated butyl rubber is used as the inner liner to maintain tire air pressure, then gas barrier properties are improved, but weight and rolling resistance increase due to large hysteresis loss
Solution Approach 1:
The patent uses a composite structure consisting of a halogenated butyl rubber layer (providing gas barrier properties) and a tie rubber layer (providing flexibility and reducing hysteresis loss). This composite material approach allows the inner liner to maintain air pressure while reducing weight and rolling resistance by combining materials with complementary properties.
Solution Approach 2:
The patent applies different material properties to different regions of the inner liner. The halogenated butyl rubber layer is positioned where gas barrier properties are most needed (in contact with the tire air space), while the tie rubber layer with lower hysteresis loss is positioned where flexibility and adherence to the carcass layer are required. This local differentiation optimizes both gas barrier performance and weight efficiency.
2Loss of energy
If a tie rubber layer is added between the inner liner and carcass layer to reduce hysteresis loss, then rolling resistance is reduced, but the thickness and weight of the inner liner assembly increase
Solution Approach 1:
The patent optimizes the thickness parameter of the tie rubber layer to a specific range (0.1-0.5 mm) to achieve the minimum necessary for reducing hysteresis loss and rolling resistance, while minimizing the added weight. By precisely controlling this parameter, the patent balances energy loss reduction with weight constraints.
3Weight of moving object
If synthetic resin coatings are applied to the inner surface to reduce weight, then weight is reduced, but adhesion between rubber and synthetic resin deteriorates
Solution Approach 1:
The tie rubber layer serves as an intermediary material between the halogenated butyl rubber inner liner and the synthetic resin coating. This intermediate layer provides compatible bonding surfaces for both materials, ensuring strong adhesion while allowing the use of lightweight synthetic resin coatings. The tie rubber's properties bridge the gap between rubber and synthetic resin interfaces.
4Weight of moving object
If thin film coatings are applied to reduce weight, then weight is reduced, but moisture resistance and film thickness uniformity deteriorate
Solution Approach 1:
The patent creates a composite structure where the halogenated butyl rubber layer provides excellent moisture resistance, compensating for the thinness of the synthetic resin coating. This composite approach allows the use of weight-reducing thin films while maintaining reliable moisture barrier properties through the inherent moisture resistance of the rubber layer.
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 laminate effectively reduces the weight and rolling resistance of pneumatic tires while maintaining excellent adhesion and moisture resistance, achieving a superior balance of gas barrier and flexibility.
Implementation Method 1
a thermoplastic resin composition (A) having an air permeation coefficient of 10×10−12 cc·cm/cm2·sec·cmHg or less
Data Source
AI summary
A laminate (C) of a thermoplastic polymer composition comprising: a thermoplastic resin composition (A) having an permeation coefficient of 10×10−12 cc·cm/cm2·sec·cmHg or less, laminated with a thermoplastic polymer composition (B) having a melt viscosity of 500-2000 Pa·s and a Young's modulus at a room temperature of 1-400 MPa, wherein the thickness of a layer of the thermoplastic resin composition (A) is 0.05-10 μm and the air permeation coefficient of the laminate (C) of 20×10−12 cc·cm/cm2·sec·cmHg or less, and a pneumatic tire using the above laminate (C) as an inner liner.