Semiconductive Cable Composition for Sag-Resistant Extrusion
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Solution Overview
Problem
The use of propylene-based resin in power cables results in non-uniform outer diameters due to sagging of the coating materials during the extrusion process, which affects insulation properties and recyclability.
Innovation Solution
A semiconductive composition is developed with specific viscosity ranges at high and low shear rates, incorporating a propylene-based resin, rubber material, and carbon black, to maintain shape stability and uniformity during extrusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If propylene-based resin is used as a resin component in power cables, then recyclability and insulation properties are improved, but outer diameter uniformity deteriorates due to sagging of coating materials during extrusion
Solution Approach 1:
The patent applies parameter changes by precisely controlling the viscosity of the semiconductive composition at different shear rates. The viscosity at high shear rate (100 s⁻¹) is set to 1000-5000 Pa·s for smooth extrusion, while viscosity at low shear rate (1 s⁻¹) is set to 100000-1000000 Pa·s to prevent sagging. This dual viscosity control resolves the contradiction between ease of extrusion and outer diameter uniformity when using propylene-based resin.
Solution Approach 2:
The patent uses composite materials by formulating a semiconductive composition that includes propylene-based resin combined with specific rubber materials or elastomers (containing at least two units from ethylene, propylene, butylene, hexene, isoprene, octene, and styrene) and carbon black. This composite formulation achieves both the desired insulation properties and the controlled viscosity characteristics needed to prevent sagging while maintaining recyclability.
2Ease of manufacture
If propylene-based resin is used to improve recyclability, then environmental friendliness is improved, but shape stability during extrusion deteriorates
Solution Approach 1:
The patent maintains shape stability during extrusion by controlling the viscosity parameters of the propylene-based resin composition. The viscosity at high shear rate (100 s⁻¹) is optimized to 1000-5000 Pa·s to ensure smooth flow and filling during extrusion, while the viscosity at low shear rate (1 s⁻¹) is optimized to 100000-1000000 Pa·s to prevent sagging and maintain shape stability after extrusion, thus preserving the integrity of recyclable cable materials.
Solution Approach 2:
The patent enhances shape stability of propylene-based resin during extrusion by creating a composite semiconductive composition that includes propylene-based resin combined with specific rubber materials or elastomers and carbon black. This composite structure provides both the recyclability benefits of propylene-based resin and the shape stability needed during the extrusion process.
3Manufacturing precision
If viscosity is increased to prevent sagging, then outer diameter uniformity is improved, but extrusion processability deteriorates
Solution Approach 1:
The patent resolves the contradiction between preventing sagging and maintaining extrusion processability by implementing parameter changes at different shear rates. The viscosity at high shear rate (100 s⁻¹) is set to 1000-5000 Pa·s to ensure smooth extrusion and good processability, while the viscosity at low shear rate (1 s⁻¹) is set to 100000-1000000 Pa·s to prevent sagging and improve outer diameter uniformity. This shear-rate-dependent viscosity control allows both requirements to be satisfied simultaneously.
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 composition ensures uniformity of the power cable's outer diameter, enhancing insulation properties and enabling recyclability while maintaining shape stability during the extrusion process.
Implementation Method 1
the semiconductive composition has a viscosity of 1000 Pa·s or more and 5000 Pa·s or less at a high shear rate with a shear rate of 100 s−1 at a temperature of 190° C., and a viscosity of 100000 Pa·s or more and 1000000 Pa·s or less at a low shear rate with a shear rate of 1 s−1 at a temperature of 190° C.
Data Source
AI summary
A semiconductive composition for forming a semiconductive layer in a power cable, the composition including: a resin component including a propylene-based resin, and at least one selected from the group of a rubber material and an elastomer; and carbon black, wherein the rubber material and the elastomer each includes at least two units from among ethylene, propylene, butylene, hexene, isoprene, octene, and styrene, and the semiconductive composition has a viscosity of 1000 Pa·s or more and 5000 Pa·s or less at a high shear rate with a shear rate of 100 s−1 at a temperature of 190° C., and a viscosity of 100000 Pa·s or more and 1000000 Pa·s or less at a low shear rate with a shear rate of 1 s−1 at a temperature of 190° C.