Halogen-Free Polymer Cable Insulation Using Ground Aluminum Hydroxide
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Solution Overview
Problem
Existing halogen-free polymer mixtures for electrical cable insulation and sheathing lack effective alternatives to precipitated aluminum hydroxide as flame retardants, which affect mechanical strength and cost efficiency.
Innovation Solution
A halogen-free polymer mixture using ground aluminum hydroxide as a flame retardant, combined with polypropylene-alkylene copolymers and optionally polyethylene, providing mechanical strength and flame resistance without the need for crosslinking agents or additional treatments, and incorporating magnesium hydroxide for enhanced performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If precipitated aluminum hydroxide is used as flame retardant, then flame resistance is achieved, but cost increases and mechanical strength decreases
Solution Approach 1:
The patent replaces expensive precipitated aluminum hydroxide with cheaper ground aluminum hydroxide as the flame retardant filler. This substitution maintains the essential flame-retardant function while significantly reducing material costs and improving mechanical properties of the polymer composition.
Solution Approach 2:
The patent changes the physical form parameter of aluminum hydroxide from precipitated to ground form, and optimizes the particle size distribution (D10, D50, D90 parameters) to achieve both flame resistance and improved mechanical strength. The specific surface area is controlled within ranges that balance flame retardancy with mechanical performance.
2Reliability
If precipitated aluminum hydroxide is used as flame retardant, then flame resistance is achieved, but manufacturing cost increases
Solution Approach 1:
The patent substitutes expensive precipitated aluminum hydroxide with economically more favorable ground aluminum hydroxide, reducing the cost per unit of flame-retardant functionality while maintaining effective fire protection performance in the polymer composition.
Solution Approach 2:
The patent extracts the essential functional property (flame retardancy) from the expensive precipitated form and achieves it through the cheaper ground form, separating the critical function from the costly material form to reduce overall manufacturing expenses.
3Strength
If ground aluminum hydroxide is used instead of precipitated aluminum hydroxide, then cost decreases and mechanical strength improves, but flame resistance may be compromised
Solution Approach 1:
The patent optimizes the particle size parameters (D10, D50, D90) and specific surface area of ground aluminum hydroxide to achieve a balance where the filler maintains effective flame-retardant performance while improving mechanical strength compared to using precipitated aluminum hydroxide.
Solution Approach 2:
The patent creates a composite polymer composition combining ground aluminum hydroxide with specific polymers (polypropylene, polyethylene, EVA) and optional crosslinking agents to achieve synergistic effects that maintain flame resistance while enhancing mechanical properties beyond what either component could provide alone.
4Strength
If crosslinking agents are added to improve mechanical strength, then strength increases, but device complexity and processing difficulty increase
Solution Approach 1:
The patent applies crosslinking optionally and partially - using crosslinking agents only when enhanced mechanical strength is required, while maintaining the capability to produce non-crosslinked versions for applications where simpler processing is preferred. This provides flexibility to optimize between strength and processing ease based on specific application requirements.
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 mixture achieves high mechanical strength, flame resistance, and cost-effectiveness by using ground aluminum hydroxide, with improved tensile strength and elongation at break, suitable for cable insulation and jackets, while maintaining low water absorption and corrosiveness.
Implementation Method 1
The ground aluminum hydroxide has a specific surface area (BET) of approximately 5 to 15 m²/g and a water absorption, determined according to ASTM C857, of maximum 15 mg/cm²
Implementation Method 2
The polymer mixture contains ground aluminum hydroxide (also called aluminum trihydroxide (ATH)) as a flame retardant
Data Source
AI summary
Halogen-free polymer mixture comprises at least one thermoplastic polymer composition comprising 0-50 phr ethylene vinyl acetate copolymer, 0-50 phr polyethylene, 20-100 phr polypropylene-ethylene copolymer and/or polypropylene, 100-250 phr ground aluminum hydroxide, 0-100 phr mineral filler, 0-10 phr additives comprising antioxidants, UV stabilizer, colorant and/or processing aid; and aluminum hydroxide as a flame retardant. A layer made of the polymer containing the polymer mixture is applied on electrical cables or lines by extruding as an insulation and/or coating. Halogen-free polymer mixture comprises at least one thermoplastic polymer composition comprising 0-50 phr ethylene vinyl acetate copolymer, 0-50 phr polyethylene, 20-100 phr polypropylene-ethylene copolymer and/or polypropylene, 100-250 phr ground aluminum hydroxide, 0-100 phr mineral filler, 0-10 phr additives comprising antioxidants, UV stabilizer, colorant and/or processing aid; and aluminum hydroxide as a flame retardant, where the ground aluminum has a specific surface area (Brunauer, Emmett and Teller) of 5-15 m 2>/g according to DIN 9277 and an average grain size of 2.5-5.5 mm according to ISO 13320-1. A layer made of the polymer containing the polymer mixture, which has a tensile strength of at least 8 MPa at room temperature and an elongation at break of at least 125%, is applied on electrical cables or lines by extruding as an insulation and/or coating.