Zirconium Phosphate Flame-Retardant Polymer for Wet-Aged Cable Insulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing halogen-free polymer compositions for wires and cables face challenges in achieving superior mechanical, electrical, and wet ageing properties while meeting stringent flame retardant standards, particularly due to high mineral filler content affecting water absorption and conductivity, which can lead to overheating and short circuits.
Innovation Solution
Incorporating a low amount of zirconium phosphate (ZrP) into the polymer composition, reducing conventional flame retardant filler content, enhances flame spread, heat release, char formation, and maintains high electrical properties, while improving elongation at break and tensile strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If large amounts of inorganic fillers (50-60 wt.-%) are added to achieve high flame retardant properties, then flame spread resistance is improved, but processability and mechanical properties deteriorate
Solution Approach 1:
The patent combines multiple flame retardant mechanisms in a single composition: magnesium hydroxide (30-60 wt.-%) and aluminum trihydroxide (10-40 wt.-%) provide bulk flame retardancy through endothermic decomposition, while zinc stearate (0.5-5 wt.-%) acts as a synergistic agent that enhances flame retardancy at lower loadings. This composite approach achieves superior flame spread resistance (SFRA > 600 seconds) while maintaining mechanical properties by avoiding excessive filler content.
Solution Approach 2:
The patent optimizes the weight percentages of each filler component to achieve the desired balance. By controlling the ratio of magnesium hydroxide to aluminum trihydroxide and limiting total filler content to 40-70 wt.-%, the composition achieves both flame retardancy and acceptable mechanical properties. The specific parameter ranges are critical to resolving the contradiction between flame spread resistance and mechanical strength.
2Object-affected harmful factors
If high mineral filler content (50-60 wt.-%) is used to achieve flame retardancy, then flame spread resistance is improved, but water absorption increases leading to higher conductivity and risk of overheating
Solution Approach 1:
Zinc stearate serves as an intermediary substance that modifies the interaction between the polymer matrix and water. This lubricant and water repellent agent reduces water absorption by coating the filler particles and polymer surface, thereby maintaining electrical properties in wet conditions while preserving flame retardancy achieved through mineral fillers.
Solution Approach 2:
The patent controls mineral filler content within specific ranges (magnesium hydroxide: 30-60 wt.-%, aluminum trihydroxide: 10-40 wt.-%) and combines it with zinc stearate (0.5-5 wt.-%) to optimize the balance between flame spread resistance and water absorption. This parameter optimization ensures that flame retardancy is achieved without excessive water uptake that would compromise electrical reliability.
3Object-affected harmful factors
If halogen-containing compounds are added to improve flame retardancy, then flame spread resistance is improved, but hazardous and corrosive gases are liberated upon burning
Solution Approach 1:
The patent converts the traditional approach of using halogen compounds (which release harmful gases) into a halogen-free system using magnesium hydroxide and aluminum trihydroxide. These fillers decompose endothermically to release water vapor and carbon dioxide instead of toxic halogen gases, while still achieving superior flame spread resistance (SFRA > 600 seconds). The harmful effect of flame spread is countered by beneficial decomposition products.
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 addition of ZrP improves small-scale flame retardancy, heat release, and wet ageing properties, maintaining high electrical performance and mechanical strength, while reducing water absorption and fabrication costs.
Implementation Method 1
Incorporating a low amount of zirconium phosphate (ZrP) into the polymer composition, reducing conventional flame retardant filler content, enhances flame spread, heat release, char formation, and maintains high electrical properties
Implementation Method 2
Such fillers, which include Al(OH)3 and Mg(OH)2 decomposes endothermically at temperatures between 200 and 600° C., liberating inert gases
Implementation Method 3
Incorporating a low amount of zirconium phosphate (ZrP) into the polymer composition, reducing conventional flame retardant filler content, enhances flame spread, heat release, char formation
Data Source
AI summary
The present invention relates to a halogen-free flame retardant polymer composition, particularly a flame retardant polymer composition comprising zirconium phosphate and further relates to a wire or cable comprising at least one layer comprising the above flame retardant polymer composition and to the use of zirconium phosphate for improving the flame retardant and/or water absorption properties of a polymer composition. The flame retardant polymer composition comprises at least (A) 2.0 to 49.8 wt.-%. based on the overall weight of the polymer composition of an ethylene copolymer containing monomer units with polar groups: (C) 30 to 65 wt.-%, based on the overall weight of the polymer composition of a flame retardant filler: (D) 2.0 to 10.0 wt.-%, based on the overall weight of the polymer composition of zirconium phosphate. and optionally (B) up to 6.0 wt.-%, based on the overall weight of the polymer composition of an ethylene homo-or copolymer and/or a propylene homo-or copolymer containing units originating from maleic acid anhydride and/or further optionally (E) up to 17.0 wt.-% based on the overall weight of the polymer composition of a copolymer of ethylene and a C4 to C10 alpha olefin comonomer having a density in the range of 860 kg/m3 to 965 kg/m3, determined according to ISO 1183.