Flame-Retardant Cable Polymer Composition With Higher Tear Strength
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Solution Overview
Problem
Current flame retardant polymer compositions for high voltage cables face challenges in meeting both mechanical and flame retardant property requirements, often exhibiting inferior tensile strength, elongation at break, and tear strength, particularly in high voltage applications as specified in IEC 60840:2020.
Innovation Solution
A flame retardant polymer composition comprising specific weight percentages of copolymers of ethylene, polyethylene and/or polypropylene, silicon fluid, magnesium hydroxide, and carbon black, optimized to achieve improved mechanical and flame retardant properties, including tensile strength, elongation at break, and tear strength, through a carefully balanced formulation of components such as methyl acrylate, maleic acid anhydride, and alpha olefin comonomers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If flame retardant compounds are used to achieve flame retardant properties, then flame retardancy is improved, but mechanical properties such as tensile strength and tear strength deteriorate
Solution Approach 1:
The patent employs a composite material system combining polyethylene base resin with multiple functional additives including magnesium hydroxide (flame retardant), silicon fluid (crack resistance), and specific copolymers (mechanical property enhancement). This composite approach allows simultaneous achievement of flame retardancy and mechanical strength by distributing functions across different components rather than relying on a single material
Solution Approach 2:
The patent optimizes the weight percentages of each component within specific ranges to balance flame retardancy and mechanical properties. By precisely controlling the concentration of magnesium hydroxide, silicon fluid, and copolymer content, the formulation achieves the required tensile strength and elongation while maintaining effective flame retardant performance
2Reliability
If flame retardant compounds are used to achieve flame retardant properties, then flame retardancy is improved, but tear strength deteriorates
Solution Approach 1:
The composite formulation includes silicon fluid or silicone gum as a specific component to address crack and tear resistance. This additive works synergistically with the flame retardant magnesium hydroxide and the copolymer blend to maintain tear strength despite the presence of flame retardant compounds
Solution Approach 2:
The silicon fluid acts as an intermediary substance that mediates between the rigid flame retardant particles and the polymer matrix, improving interfacial adhesion and crack propagation resistance, thereby preventing tear strength deterioration
3Reliability
If flame retardant materials are used to achieve flame retardant properties, then flame retardancy is improved, but cracking resistance deteriorates
Solution Approach 1:
Silicon fluid or silicone gum serves as a crack-resistant intermediary component that prevents the formation and propagation of cracks in the cable jacket, especially under thermal stress and mechanical loading conditions
Solution Approach 2:
The patent specifies precise weight percentage ranges for silicon fluid (0.1-3.0 wt%) to optimize crack resistance without compromising flame retardancy. This parameter optimization ensures the material maintains flexibility and crack resistance while containing sufficient flame retardant content
4Reliability
If flame retardant polymer compositions are formulated to meet flame retardant requirements, then flame retardancy is improved, but elongation at break deteriorates
Solution Approach 1:
The patent uses a composite system with specific copolymers (ethylene-methyl acrylate, ethylene-methyl methacrylate, or ethylene-acrylic acid copolymers) that maintain polymer chain flexibility and elongation capability even with high magnesium hydroxide content for flame retardancy
Solution Approach 2:
The patent optimizes the copolymer composition and weight percentage (2.0-15.0 wt% of specific copolymers) to maintain sufficient elongation at break while achieving the required flame retardant performance through controlled magnesium hydroxide content
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 demonstrates enhanced tensile strength, elongation at break, and tear strength, meeting the stringent requirements of high voltage cables while maintaining effective flame retardancy, as evidenced by improved performance in cone calorimeter tests and mechanical property retention after thermal aging.
Implementation Method 1
a copolymer of ethylene and acrylic acid, a copolymer of ethylene and maleic acid, or a graft copolymer of polyethylene and maleic acid anhydride
Implementation Method 2
a copolymer of ethylene comprising units selected from the group consisting of methyl acrylate, methyl methacrylate or mixtures thereof
Data Source
AI summary
The present invention relates to a flame retardant polymer composition comprising (A) 2.0 to 15.0 wt % of a copolymer of ethylene comprising units selected from the group consisting of methyl acrylate, methyl methacrylate or mixtures thereof; (B) 0 to 4.0 wt % of a polyethylene and/or polypropylene containing units originating from maleic acid anhydride; (C) 0.1 to 3.0 wt % of a silicon fluid and/or silicone gum; (D) 40.0 to 55.0 wt % of a magnesium hydroxide; (E) 2.0 to 15.0 wt % of a copolymer of ethylene and alpha olefin comonomer units having from 4 to 10 carbon atoms, which has a density of from 860 to 910 kg/m3, determined according to ISO 1183; (F) 18.0 to 35.0 wt % of a copolymer of ethylene and alpha olefin comonomer units having from 4 to 10 carbon atoms, which has a density of from 920 to 960 kg/m3, determined according to ISO 1183, and a melt flow rate MFR5 of from 0.05 to 2.50 g/10 min, determined according to ISO 1133 at a temperature of 190° C. and a load of 5.0 kg; and (G) 0 to 8.0 wt % of carbon black, wherein all weight percentages are based on the total weight of the flame retardant polymer composition; an article, such as a wire or cable, comprising said flame retardant polymer composition; and the use of said flame retardant polymer composition for the production of an article, such as a wire or cable.