Semiconductive Cable Copolymer Composition Low-Temperature Impact
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Solution Overview
Problem
Existing semiconductive polymer compositions for cables lack a balance between mechanical properties at high and low temperatures, and they do not provide sufficient impact strength and flexibility, especially at low temperatures.
Innovation Solution
A polymer composition comprising a propylene polymer, a polar copolymer, a solid conductive filler, and optionally a polyolefin functionalized with a mono- or polycarboxylic acid compound, which achieves high Charpy Notch Impact Strength and flexibility at both high and low temperatures, with the polar copolymer enhancing impact strength and the functionalized polyolefin maintaining volume resistivity during elevated temperature aging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If existing semiconductive polymer compositions are used, then the cable layer provides basic semiconductive properties, but the mechanical properties (impact strength and flexibility) are insufficient especially at low temperatures
Solution Approach 1:
The patent uses a composite material system consisting of propylene polymer matrix combined with elastomeric copolymer particles (containing polar groups) and conductive filler. This composite structure allows the propylene polymer to provide structural integrity while the elastomeric copolymer particles provide impact strength and flexibility enhancement, particularly at low temperatures where the elastomeric phase remains flexible and absorbs impact energy effectively.
Solution Approach 2:
The patent modifies the chemical parameters of the copolymer by incorporating polar groups (such as carboxyl, hydroxyl, or ether groups) into the elastomeric phase. This parameter change in the copolymer structure improves interfacial adhesion with the propylene polymer matrix and enhances the overall mechanical properties, particularly impact strength and flexibility at low temperatures, while maintaining the semiconductive characteristics.
2Stability of the object's composition
If existing semiconductive polymer compositions are used, then the cable layer provides basic electrical properties, but the balance between mechanical properties at high and low temperatures is lacking
Solution Approach 1:
The composite material system combines propylene polymer with elastomeric copolymer particles containing polar groups. The propylene polymer matrix provides thermal stability and structural integrity at high temperatures, while the elastomeric copolymer particles maintain flexibility and impact resistance at low temperatures. This composite structure achieves a balanced performance across a wide temperature range.
Solution Approach 2:
The patent applies local quality by distributing elastomeric copolymer particles throughout the propylene polymer matrix. These particles are locally dispersed to provide targeted flexibility and impact strength enhancement in specific regions, while the bulk propylene polymer maintains its thermal stability and structural properties. This localized modification achieves overall balanced mechanical properties across temperature extremes.
3Reliability
If carbon black is added to achieve percolation threshold, then electrical conductivity is improved, but the mechanical properties and flexibility are reduced
Solution Approach 1:
The elastomeric copolymer particles containing polar groups act as an intermediary between the propylene polymer matrix and the conductive filler. These particles improve the dispersion and distribution of conductive filler throughout the matrix, ensuring adequate electrical conductivity through enhanced percolation network formation, while simultaneously maintaining mechanical strength and flexibility by providing a flexible matrix structure that accommodates the conductive filler without excessive stiffening.
Data Source
AI summary
Described herein are polymer compositions useful as a semiconductive layer suitable for cables. The polymer compositions include (a) a heterophasic copolymer of propylene, (b) a polar copolymer having a polar comonomer having polar groups, (c) a solid conductive filler, and optionally (d) a polyolefin functionalised with a mono- or polycarboxylic acid compound or a derivative of a mono- or polycarboxylic acid compound, wherein said compostion is not crosslinked by the addition of a crosslinking agent. Also described herein is a process for producing the polymer compositions as well as the use of the compositions thereof.