Cable Insulation Polymer Blend Without Crosslinking Degassing
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Solution Overview
Problem
Current polymer compositions used in cable insulation layers, particularly in high voltage applications, face challenges with creep resistance and require crosslinking processes that involve costly degassing steps and peroxide decomposition products, which can negatively impact electrical properties.
Innovation Solution
A polymer blend comprising at least 40 wt% low density polyethylene (LDPE), a polypropylene homopolymer, and a random heterophasic polypropylene copolymer, which eliminates the need for crosslinking and reduces creep strain, thereby enhancing thermomechanical properties without the need for degassing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If crosslinking is used to improve thermomechanical properties and creep resistance, then temperature resistance improves, but the process becomes more complex and costly due to degassing steps
Solution Approach 1:
The invention extracts and eliminates the crosslinking step from the cable insulation manufacturing process. By using a thermoplastic polymer composition with specific molecular weight and branching characteristics, the patent removes the need for crosslinking entirely, thereby eliminating the associated degassing steps and process complexity while maintaining adequate thermomechanical properties
Solution Approach 2:
The invention changes the molecular parameters of the polyethylene by specifying a molecular weight of at least 100,000 g/mol and a branching content of at least 5 branches per 1000 carbon atoms. These parameter changes enable the thermoplastic material to achieve the necessary creep resistance and thermomechanical performance without requiring crosslinking
2Strength
If crosslinking with peroxides is used to enhance mechanical strength, then mechanical strength improves, but harmful volatile decomposition products are generated
Solution Approach 1:
The invention converts the harmful effect of peroxide decomposition by eliminating peroxide use entirely. Instead of trying to manage or remove the harmful volatile products, the patent uses a thermoplastic composition that achieves mechanical strength through molecular weight and branching structure, completely avoiding the generation of harmful decomposition products
Solution Approach 2:
The invention uses a conventional thermoplastic polymer composition that can be processed and discarded without the need for complex crosslinking and degassing procedures. The material achieves its performance through inherent molecular characteristics rather than through chemical modification that generates harmful by-products
3Stability of the object's composition
If crosslinking is used to improve creep resistance, then creep properties improve, but production time increases due to additional processing steps
Solution Approach 1:
The invention extracts and eliminates the crosslinking step from the manufacturing process. By using a thermoplastic polymer composition with specific molecular weight and branching characteristics, the patent removes the need for crosslinking entirely, thereby eliminating the associated degassing steps and process complexity while maintaining adequate thermomechanical properties
Solution Approach 2:
The invention performs the creep resistance enhancement in advance during polymer synthesis rather than during cable manufacturing. The polyethylene is produced with high molecular weight and specific branching content before extrusion, so the creep resistance is built-in from the start, eliminating the need for subsequent crosslinking steps
Data Source
AI summary
A polymer composition comprising: (i) at least 40 wt % LDPE; (ii) a polypropylene homopolymer; and (iii) a random heterophasic polypropylene copolymer.