Polyamide-olefin elastomer crosslinking for heat and solvent resistance
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Solution Overview
Problem
Thermoplastic elastomers known in the prior art fail to achieve a combination of low hardness, good elastic properties, rapid recovery, solvent resistance, and heat resistance, with existing materials either excelling in elastic properties or heat resistance but not both, and being costly for high heat resistance applications.
Innovation Solution
Crosslinkable compositions comprising 5-50% polyamide, 20-95% α-olefin-vinyl acetate copolymer, with a free-radical crosslinking initiator and co-crosslinking agent, allowing for the production of thermoplastic elastomers with excellent heat resistance, solvent resistance, and elastic properties across a wide hardness range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermoplastic elastomers are designed for high heat resistance and solvent resistance, then these properties are improved, but elastic properties and recovery characteristics deteriorate
Solution Approach 1:
The invention divides the material into two distinct phases: a thermoplastic polyamide matrix providing heat and solvent resistance, and a crosslinked elastomer disperse phase providing elastic properties. This segmentation allows each phase to independently contribute its specialized properties without compromising the other.
Solution Approach 2:
The invention creates a composite material system combining polyamide (thermoplastic) and crosslinked elastomer (thermoset) phases. The polyamide matrix provides structural integrity and resistance to heat/solvents, while the embedded crosslinked elastomer particles provide reversible elastic deformation, achieving a synergistic combination of previously conflicting properties.
2Strength
If the hardness of thermoplastic elastomers is reduced for better elasticity, then elastic properties are improved, but heat resistance and mechanical strength deteriorate
Solution Approach 1:
The material is segmented into a hard thermoplastic matrix and soft crosslinked elastomer particles. The hardness is primarily determined by the polyamide matrix which maintains heat resistance, while the soft elastomer particles provide elastic compliance. This segmentation decouples the relationship between hardness and heat resistance.
Solution Approach 2:
Different regions of the material have different local properties: the polyamide matrix regions provide heat resistance and structural strength, while the elastomer particle regions provide local compliance and elastic recovery. This local quality differentiation allows the bulk material to exhibit both hardness and elasticity simultaneously.
3Temperature
If crosslinking agents are added to improve heat resistance, then thermal stability is improved, but processing complexity and cost increase
Solution Approach 1:
The crosslinking function is extracted from the continuous matrix and concentrated into discrete elastomer particles. Only these particles require crosslinking agents and undergo crosslinking reactions, while the polyamide matrix remains thermoplastic and easy to process. This extraction reduces the overall complexity of the processing system.
Solution Approach 2:
Instead of crosslinking the entire material system, crosslinking is applied partially only to the elastomer phase. This partial action achieves the necessary thermal stability through the crosslinked particles without requiring complex processing for full-system crosslinking, maintaining relative simplicity in manufacturing.
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 resulting thermoplastic elastomers exhibit excellent heat resistance, solvent resistance, and elastic properties with a low hardness range, enabling processing via various techniques and suitable for applications requiring high temperature and solvent resistance.
Implementation Method 1
with from 0.2 to 10 parts by weight per 100 parts by weight of the α-olefin-vinyl acetate copolymer (phr), particularly preferably from 1 to 6 phr, of at least one free-radical crosslinking initiator, as component D
Data Source
AI summary
Crosslinkable compositions based on polyamide and on α-olefin-vinyl acetate copolymers, where the compositions comprise a crosslinking initiator, and also a co-crosslinking agent, and crosslinkable compositions based on polyamides and on α-olefin-vinyl acetate copolymers, where these compositions comprise a crosslinking initiator and the amount of polyamide in the compositions is <30% by weight. The present invention further relates to the preparation of the crosslinkable compositions of the invention, to the use of the crosslinkable compositions of the invention for the production of thermoplastic elastomers, to a process for the crosslinking of the compositions of the invention to give a thermoplastic elastomer, and also to the thermoplastic elastomers themselves and to their use for the production of mouldings.