Homophasic Polymer Cable Insulation for High-Temperature Breakdown Resistance
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Solution Overview
Problem
Existing electric cable insulating layers based on heterophasic copolymers of propylene lack optimal thermo-mechanical properties and resistance to electrical breakdown, particularly at high temperatures.
Innovation Solution
A polymer composition comprising a first homophasic propylene polymer with an elastic modulus greater than 300 MPa and a second homophasic ethylene polymer with an elastic modulus of at most 300 MPa, where the propylene polymer constitutes a higher weight percentage, along with optional nano-fillers, is used to enhance mechanical resistance and dielectric strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heterophasic copolymer of propylene is used for insulating layer, then manufacturing is easier, but resistance to electrical breakdown and thermo-mechanical properties are insufficient
Solution Approach 1:
The patent uses a composite polymer system combining homophasic propylene polymer with high elastic modulus (>300 MPa) and homophasic ethylene polymer with low elastic modulus (≤300 MPa). This composite approach achieves optimal balance between electrical breakdown resistance and thermo-mechanical properties, resolving the contradiction by integrating materials with complementary characteristics rather than using a single heterophasic copolymer.
Solution Approach 2:
The patent specifies precise parameter ranges for the polymer components: elastic modulus of propylene polymer >300 MPa, elastic modulus of ethylene polymer ≤300 MPa, and weight ratio of propylene to ethylene polymer >1. By controlling these parameters, the composition achieves improved electrical breakdown resistance while maintaining manufacturability through well-defined material specifications.
2Reliability
If heterophasic copolymer is used, then processing is simpler, but resistance to deformation at high temperature is poor
Solution Approach 1:
The patent combines homophasic propylene polymer (high elastic modulus >300 MPa) providing thermal stability with homophasic ethylene polymer (low elastic modulus ≤300 MPa) providing flexibility. This composite structure maintains cable geometry at temperatures ≥90°C while remaining processable, resolving the contradiction between high-temperature resistance and composition complexity.
Solution Approach 2:
The patent assigns different functional roles to different polymer components: the homophasic propylene polymer with high elastic modulus provides structural stability and resistance to deformation at high temperature, while the homophasic ethylene polymer with low elastic modulus provides flexibility and processability. This functional differentiation within the composite resolves the contradiction by optimizing local material properties for specific requirements.
3Strength
If higher elastic modulus polymer is used, then mechanical strength improves, but flexibility and resistance to deformation at high temperature deteriorate
Solution Approach 1:
The patent creates a composite system where homophasic propylene polymer (elastic modulus >300 MPa) provides mechanical strength and structural integrity, while homophasic ethylene polymer (elastic modulus ≤300 MPa) provides flexibility and adaptability. The synergistic combination resolves the contradiction by distributing functional requirements across complementary materials rather than relying on a single polymer with conflicting properties.
Solution Approach 2:
The patent optimizes the elastic modulus parameter by selecting propylene polymer with elastic modulus >300 MPa and ethylene polymer with elastic modulus ≤300 MPa, creating a balanced composite. Additionally, the weight ratio parameter is controlled (propylene polymer weight > ethylene polymer weight) to ensure mechanical strength dominance while maintaining flexibility, resolving the contradiction through precise parameter control.
Data Source
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AI summary
The present invention relates to a polymer composition characterized in that it comprises: - at least one first homophasic polymer of propylene, and - at least one second homophasic polymer of ethylene, said second polymer having an elastic modulus of at most 300 MPa, determined according to ISO 527-1, -2 (2012), the amount by weight of the first polymer being greater than the amount by weight of the second polymer, relative to the total weight of the polymer composition.