Elastomer Composition Island-in-Sea Structure
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Solution Overview
Problem
Conventional thermoplastic elastomer compositions face limitations in increasing the rubber content while maintaining the thermoplastic resin's properties, as excessive rubber inversion leads to loss of fluidity and molding issues.
Innovation Solution
An elastomer composition with a thermoplastic resin matrix and a finely dispersed elastomer component, where the volume ratio and melt viscosity satisfy specific formulas, allowing for an increased elastomer ratio and inclusion of a plasticizer that is later removed, forming an island-in-sea structure for enhanced flexibility and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a large amount of rubber is compounded in the thermoplastic elastomer composition, then the elastomer content is increased to improve flexibility and low temperature durability, but the thermoplastic resin and elastomer component invert in phase, causing loss of fluidity and making shaping impossible
Solution Approach 1:
The invention changes the physical state parameters of the elastomer component by controlling its glass transition temperature (Tg) to be -50°C or lower. This parameter change allows the elastomer to remain in a rubbery state during processing while maintaining high elastomer content (70-95 volume%), thus preventing phase inversion and preserving shaping capability despite the high elastomer concentration.
Solution Approach 2:
The invention utilizes phase transition characteristics by selecting elastomers with specific glass transition temperatures. The elastomer component is chosen to have Tg ≤ -50°C, ensuring it remains in a flexible rubbery phase during normal processing temperatures, while the thermoplastic resin maintains its crystalline phase. This phase relationship prevents inversion even at high elastomer contents, solving the contradiction between elastomer quantity and shaping capability.
2Reliability
If a large amount of rubber is compounded to achieve flexible and low temperature durable elastomer, then the elastomer content is increased, but the continuous phase and dispersed phase invert, resulting in loss of thermoplastic resin fluidity
Solution Approach 1:
The invention modifies the temperature parameter characteristic of the elastomer by selecting materials with glass transition temperature of -50°C or lower. This ensures the elastomer maintains its rubbery properties and flexibility at low temperatures while preserving the island-in-sea phase structure stability during processing, even at high elastomer concentrations of 70-95 volume%.
3Ease of manufacture
If the amount of thermoplastic resin is increased to maintain fluidity and shaping capability, then the continuous phase proportion is increased, but the flexibility and low temperature durability of the elastomer composition deteriorate
Solution Approach 1:
The invention changes the glass transition temperature parameter of the elastomer component to -50°C or lower, which allows the elastomer to maintain flexibility and rubbery characteristics even when present in high volumes (70-95%). This eliminates the need to increase thermoplastic resin content for fluidity, as the modified elastomer itself provides both flexibility and processability.
Solution Approach 2:
The invention creates a composite material system where the elastomer component with Tg ≤ -50°C forms the dispersed phase islands within the thermoplastic resin continuous phase. This composite structure, with specific phase distribution and elastomer characteristics, achieves both high flexibility from the elastomer and adequate fluidity from the resin matrix, without requiring high resin content.
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 enables the production of a flexible, low-temperature durable elastomer composition that maintains thermoplastic resin characteristics, suitable for applications like pneumatic tire inner liners with improved heat resistance, low gas permeability, and dynamic durability.
Implementation Method 1
removing the plasticizer (D) by evaporation, extraction or migration
Data Source
AI summary
An elastomer composition, having an excellent flexibility and low temperature durability, a method for producing the same and a pneumatic tire using the same are provided. An elastomer composition (C) comprising a matrix of a thermoplastic resin (A), in which a dispersed phase of an elastomer component (B) is finely dispersed to form an island-in-sea structure, wherein volume ratios of the thermoplastic resin (A) and the elastomer component (B) satisfy the following formula (I):φd/φm>ηd/ηm (I)wherein φd and ηd, respectively, indicate a volume ratio and a melt viscosity of the elastomer component (B), and φm and ηm, respectively, indicate a volume ratio and a melt viscosity of the thermoplastic resin (A)), a method for producing the same and a pneumatic tire using the same.