Crosslinked Propylene Copolymers for High-Temperature Elasticity
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Solution Overview
Problem
Conventional elastic materials, such as Spandex™, lose integrity and elastic properties at elevated temperatures, making them unsuitable for high-temperature applications like co-knitting with polyester fibers, and there is a need for propylene-based materials with improved thermal resistance and elasticity.
Innovation Solution
Crosslinkable propylene-based copolymers are developed by blending propylene-derived units with dienes, vinyl siloxane, and peroxide, which can be extruded and crosslinked at temperatures above 30°C and high humidity, resulting in fibers and films with enhanced elastic and thermal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional elastic materials like Spandex are used, then good stretchability and elasticity are achieved at room temperature, but integrity and elastic properties are lost at elevated temperatures
Solution Approach 1:
The patent applies parameter changes by introducing crosslinking chemistry to fundamentally alter the thermal behavior of the polymer. The propylene-based copolymer is modified to include crosslinkable functional groups that form a three-dimensional network structure, changing the material from a thermoplastic to a thermosetting system that maintains integrity at elevated temperatures up to 200°C.
Solution Approach 2:
The patent creates a composite elastomeric composition by combining propylene-based copolymer with crosslinking agents and functional additives. This composite structure integrates the elasticity of the polymer matrix with the thermal stability of the crosslinked network, achieving both stretchability and heat resistance simultaneously.
2Temperature
If propylene-based copolymers are crosslinked to improve thermal resistance, then integrity at elevated temperatures is maintained, but processing complexity increases
Solution Approach 1:
The patent applies preliminary action by incorporating crosslinking agents and functional groups into the polymer formulation before processing. The crosslinking chemistry is pre-prepared in the extrudable composition, allowing the crosslinking reaction to occur automatically during or after the extrusion process without requiring separate complex processing steps.
Solution Approach 2:
The patent implements self-service by designing a formulation where the crosslinking reaction occurs automatically under the extrusion conditions themselves. The peroxide initiators and crosslinking agents are activated by the heat and shear during extrusion, causing the crosslinking to happen selflessly as part of the normal processing rather than requiring additional equipment or complex controls.
3Reliability
If crosslinking is performed at high temperature and humidity, then elastic and thermal performance is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies parameter changes by optimizing the crosslinking conditions to occur within a broad range of temperatures (above 30°C) and humidity levels (50% or above). This wide operating window for crosslinking reduces the need for precise control during manufacturing, as the reaction proceeds effectively under normal processing conditions without requiring tightly controlled environmental parameters.
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 crosslinked propylene-based copolymers maintain their elastic and thermal performance, providing improved integrity and stability at elevated temperatures compared to uncrosslinked compositions, suitable for various applications including clothing and automotive trim.
Implementation Method 1
crosslinkable propylene-based copolymers... which can be extruded and crosslinked at temperatures above 30°C and high humidity
Implementation Method 2
blending an elastomeric composition comprising at least one propylene-based polymer comprising propylene derived units and one or more dienes... about 0.5 wt % to about 10 wt % vinyl siloxane; and about 0.1 wt % to about 1.0 wt % peroxide
Data Source
AI summary
Provided are crosslinkable propylene-based copolymers, methods for making the same, elastomeric compositions including the same, and articles made therefrom, e.g., films and fibers. Exemplary elastomeric compositions are composed of at least one propylene-based polymer comprising propylene derived units and one or more dienes, the propylene-based polymer having a triad tacticity of from 50% to 99% and a heat of fusion of less than 80 J/g; about 0.5 wt % to about 10 wt % vinyl siloxane; and about 0.1 wt % to about 1.0 wt % peroxide. The elastomeric compositions can be extruded and crosslinked at a temperature of at least about 50° C. and a relative humidity of at least about 90% to provide a crosslinked elastomeric composition. The crosslinked elastomeric compositions are particularly useful for making fibers and films.