Silane Crosslinkable Polymer Composition for Cable Insulation
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Solution Overview
Problem
Silane crosslinkable polymer compositions used in wire and cable applications, particularly in power cables, face challenges with long crosslinking times and demanding conditions due to thick insulation layers, which affect production efficiency and cost-effectiveness.
Innovation Solution
A polymer composition with a melt flow rate (MFR) of less than 0.80 g/10 min, combined with a scorch retarding compound, enhances crosslinking speed and reduces the need for elevated temperatures, allowing for faster and milder crosslinking of cables with improved mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If silane crosslinkable polymer composition is used in power cables with thick insulation layers, then mechanical strength and chemical resistance are improved, but crosslinking time becomes excessively long and requires elevated temperatures
Solution Approach 1:
The patent changes the molecular weight parameter of the polyolefin by using a mixture of high molecular weight polyolefin (HMWPO) and low molecular weight polyolefin (LMWPO), which alters the melt flow rate and enables faster crosslinking. This parameter change resolves the contradiction by allowing adequate mechanical strength while reducing crosslinking time to 1-4 hours at ambient temperature or 30 minutes at elevated temperature.
Solution Approach 2:
The patent creates a composite polymer system by combining HMWPO and LMWPO in specific ratios (0.1-10 wt% LMWPO content). This composite approach allows the material to exhibit both the mechanical strength of HMWPO and the faster crosslinking capability of LMWPO, resolving the time-strength contradiction.
2Strength
If silane crosslinkable polymer composition is used in power cables with thick insulation layers, then mechanical strength and chemical resistance are improved, but crosslinking requires demanding elevated temperature conditions
Solution Approach 1:
The patent changes the melt flow rate parameter by controlling the LMWPO content in the polyolefin mixture, which enables the crosslinking reaction to proceed at lower temperatures. This resolves the contradiction by allowing adequate mechanical strength to be achieved at ambient temperature or mildly elevated temperatures (up to 100°C) rather than requiring high temperature conditions.
3Ease of manufacture
If conventional polyolefin with higher melt flow rate is used, then processability is improved, but crosslinking speed becomes slow affecting production efficiency
Solution Approach 1:
The patent optimizes the melt flow rate parameter by incorporating LMWPO (0.1-10 wt%) into the HMWPO matrix. This creates a balanced MFR (0.5-5 g/10min) that provides both adequate processability for extrusion and fast crosslinking speed (1-4 hours at ambient temperature), resolving the contradiction between ease of manufacture and production efficiency.
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 polymer composition enables faster and more efficient crosslinking of cables, particularly in power cables with thick insulation layers, at ambient temperatures, reducing production time and costs while maintaining excellent mechanical properties and surface quality.
Implementation Method 1
via hydrolysable silane groups present in the polymer using a condensation catalyst in the presence of water
Implementation Method 2
hydrolysable silane groups are typically then crosslinked by hydrolysis and subsequent condensation in the presence of a silanol condensation catalyst and H2O
Data Source
AI summary
The invention is directed to a silane crosslinkable polymer composition which comprises a polyolefin (a) bearing hydrolysable silane group(s) containing units. The polymer composition is suitable for producing crosslinkable articles, preferably one or more layers of a cable. The formed article, preferably a cable, is preferably crosslinked before the enduse thereof.