Modified Polypropylene Cable Layer for Low Temperature Toughness
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Solution Overview
Problem
Current cable layers based on polyethylene face challenges with toughness at low temperatures and high temperature performance, while polypropylene alternatives struggle with processing speed and mechanical properties.
Innovation Solution
A cable layer composed of a heterophasic propylene copolymer with high ethylene content, chemically modified by bifunctionally unsaturated compounds, offering improved toughness, temperature performance, and high-speed extrusion capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If crosslinked polyethylene is used for cable insulation, then high temperature performance is improved, but toughness at low temperatures deteriorates due to remaining crystalline fraction melting at 110°C
Solution Approach 1:
The patent changes the fundamental material parameter from polyethylene to polypropylene base polymer, which has a higher melting point (160-170°C) than polyethylene (110°C). This parameter change enables the cable layer to maintain structural integrity at higher temperatures while improving low-temperature toughness through the specific heterophasic copolymer structure with controlled crystallinity.
Solution Approach 2:
The patent creates a composite material system by chemically modifying the polypropylene copolymer with bifunctionally unsaturated compounds (such as silanes). This chemical modification creates a crosslinked network structure within the thermoplastic matrix, combining the advantages of both thermoplastic processing and crosslinked high-temperature performance, thereby resolving the contradiction between low-temperature toughness and high-temperature stability.
2Strength
If polypropylene is used to replace polyethylene in cable layers, then low temperature toughness is improved, but processing speed and mechanical properties deteriorate
Solution Approach 1:
The patent optimizes the molecular weight distribution and comonomer content parameters of the polypropylene copolymer to achieve a balance between processability and mechanical properties. The specific heterophasic structure with controlled phase distribution enables the material to be extruded at high line speeds while maintaining excellent toughness and mechanical performance.
3Strength
If polypropylene copolymer is used for cable insulation, then low temperature toughness is improved, but high temperature performance and mechanical properties deteriorate
Solution Approach 1:
The patent creates a composite material system by chemically modifying the polypropylene copolymer with bifunctionally unsaturated compounds (such as silanes). This chemical modification creates a crosslinked network structure within the thermoplastic matrix, combining the advantages of both thermoplastic processing and crosslinked high-temperature performance, thereby resolving the contradiction between low-temperature toughness and high-temperature stability.
4Strength
If heterophasic propylene copolymer with high ethylene content is used, then toughness and flexibility are improved, but processing at high line speeds becomes difficult
Solution Approach 1:
The patent optimizes the molecular weight distribution and comonomer content parameters of the polypropylene copolymer to achieve a balance between processability and mechanical properties. The specific heterophasic structure with controlled phase distribution enables the material to be extruded at high line speeds while maintaining excellent toughness and mechanical performance.
Data Source
AI summary
Cable layer including a propylene polymer composition including (a) a propylene polymer (b) an elastomeric copolymer of propylene and at least one comonomer selected from the group consisting of ethylene, C4 α-olefin, C5 α-olefin, C6 α-olefin, C7 α-olefin, C8 α-olefin, C9 α-olefin and C10 α-olefin, and (c) units derived from at least bifunctionally unsaturated monomer(s) and/or at least multifunctionally unsaturated low molecular weight polymer(s), the units being linked to the propylene polymer and/or the elastometric copolymer wherein the gel content of the propylene polymer composition determined as the amount of polymer insoluble in boiling xylene is not more than 1 wt %.