Crosslinkable Polymer Composition for Cable Extrusion
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Solution Overview
Problem
Existing polymer compositions for crosslinked cables face challenges in achieving high processability without causing sagging issues, which limits their mechanical properties and production efficiency due to premature crosslinking and scorch formation during extrusion.
Innovation Solution
A polymer composition with a melt flow rate of at least 2.3 g/10 min and carbon-carbon double bonds of at least 0.40 per 1000 carbon atoms, combined with a crosslinking agent, enhances processability and crosslinking efficiency while preventing premature crosslinking, thereby maintaining dimensional stability and reducing sagging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the melt flow rate (MFR) of the polymer material is increased to improve processability and reduce melt temperature, then extrusion speed and productivity are improved, but the polymer becomes too flowable causing sagging and non-centric cable formation
Solution Approach 1:
The invention changes the chemical composition parameters of the polymer by incorporating unsaturated polymers with specific double bond contents (at least 0.40 per 1000 carbon atoms) and controlling MFR to at least 2.3 g/10 min. This parameter optimization allows the polymer to maintain adequate flowability for high-speed extrusion while preventing excessive sagging that would compromise cable centricity.
Solution Approach 2:
The invention creates a composite polymer composition by combining unsaturated polymers with crosslinking agents. The unsaturated polymer provides the necessary flow characteristics for high productivity, while the crosslinking agent enables subsequent crosslinking to achieve the desired mechanical properties and dimensional stability without requiring excessive flowability during extrusion.
2Ease of manufacture
If the extrusion temperature is increased to improve melting and homogenization, then processability is improved, but the crosslinking agent decomposes prematurely causing scorch formation
Solution Approach 1:
The invention optimizes the extrusion temperature parameter to a specific range that balances two competing requirements: high enough to ensure proper melting and homogenization of the polymer, but low enough to prevent premature decomposition of the crosslinking agent. This parameter control prevents scorch formation while maintaining ease of manufacture.
Solution Approach 2:
The unsaturated polymer acts as an intermediary medium that facilitates heat transfer and homogenization during extrusion without triggering crosslinking. Its specific molecular structure with controlled double bond content allows it to withstand the extrusion temperature range without causing premature crosslinking or scorch, while still enabling proper melting and mixing.
3Productivity
If the crosslinking speed is increased by elevating temperature to improve crosslinking efficiency, then crosslinking performance is improved, but the risk of scorch formation increases
Solution Approach 1:
The invention prepares the polymer composition in advance with controlled unsaturation levels and selects crosslinking agents with appropriate decomposition characteristics. This preliminary preparation ensures that during the subsequent crosslinking step, the reaction proceeds efficiently at elevated temperatures without triggering premature decomposition or scorch formation.
Solution Approach 2:
The invention optimizes the crosslinking temperature parameter to achieve high crosslinking efficiency while avoiding scorch. By controlling the temperature profile and the chemical composition (unsaturation level, crosslinking agent selection), the process achieves rapid crosslinking without exceeding the decomposition threshold of the crosslinking agent.
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 proposed polymer composition improves extrusion speed and productivity by maintaining high quality and rigidity in crosslinked cables, reducing scorch formation, and allowing for higher output rates with improved processing conditions.
Implementation Method 1
Crosslinking can be effected with crosslinking agents which decompose generating free radicals
Implementation Method 2
Crosslinking of polymers, e.g. polyolefins, substantially contributes to an improved heat and deformation resistance, creep properties, mechanical strength, chemical resistance and abrasion resistance of a polymer
Implementation Method 3
The melt temperature can be reduced by increasing melt flow rate (MFR) of the polymer material. A polymer with increased MFR (i.e. less viscose with lower viscosity value) would enable to increase the out put, to reduce melt pressure or to reduce melt temperature
Data Source
AI summary
A Polymer Composition comprising at least one unsaturated polymer, and optionally a crosslinking agent.