Flame Retardant Cable Polymer Composition
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Solution Overview
Problem
Current flame retardant polymer compositions for cables and wires, particularly conduit and automotive wires, face challenges in achieving improved flame retardancy, mechanical properties, and processing behavior, including abrasion resistance and performance in single wire burning tests, while avoiding the use of halogen-containing compounds and maintaining compatibility with polyolefin materials.
Innovation Solution
A polymer composition comprising an olefin homo- and/or copolymer, a silicone-group containing compound, and an inorganic filler, with a specific MFR2 ratio under defined conditions, is used to create a flame retardant layer that enhances flame retardancy, abrasion resistance, and processing properties, and is produced in a continuous process for industrial-scale cable production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If halogen-based chemicals or phosphate based chemicals are incorporated into polyolefin to improve flame resistance, then flame retardancy is improved, but mechanical properties and processability deteriorate due to high loading levels required
Solution Approach 1:
The invention changes the chemical composition parameters by using silicon-group containing compounds and inorganic fillers instead of traditional halogen or phosphate additives. This substitution allows achieving flame retardancy with different chemical mechanisms that do not require high loading levels, thereby preserving mechanical properties
Solution Approach 2:
The invention creates a composite flame retardant system combining silicon-group containing compounds with inorganic fillers (such as metal oxides or hydroxides). This composite approach provides synergistic effects where the combination delivers superior flame retardancy at lower overall loading levels compared to single additives, thus maintaining better mechanical properties
2Reliability
If high loading levels of flame retardant additives are used to achieve good flame retardancy, then flame retardant properties are improved, but abrasion resistance deteriorates
Solution Approach 1:
The invention changes the additive composition from traditional high-loading requirements to a silicon-based system that achieves flame retardancy at lower concentrations. This parameter change in chemical composition directly improves abrasion resistance while maintaining flame retardant performance
Solution Approach 2:
The silicon-group containing compounds form a protective char layer during combustion that acts as a temporary barrier. This layer provides flame protection during the critical burning phase without requiring permanent structural modification to the polymer matrix, thus preserving long-term mechanical integrity and abrasion resistance
3Reliability
If conventional flame retardant compositions are used to achieve good flame retardancy, then limiting oxygen index performance is improved, but single wire burning test performance and processing properties deteriorate
Solution Approach 1:
The invention changes the chemical composition to silicon-based flame retardants that are more compatible with polyolefin matrices. This compositional change improves processing properties such as melt flow and extrusion behavior while maintaining or enhancing flame retardant performance in practical burning scenarios
4Reliability
If flame retardant additives are incorporated to improve flame retardancy, then fire resistance is improved, but compatibility with polyolefin material deteriorates
Solution Approach 1:
The silicon-group containing compounds act as intermediaries between the polyolefin matrix and the inorganic fillers. These silicon compounds improve interfacial compatibility and dispersion of inorganic particles within the polyolefin, preventing phase separation and maintaining material homogeneity while enabling effective flame retardancy
Solution Approach 2:
The invention creates a tri-component composite system where silicon-group compounds bridge the organic polyolefin matrix and inorganic fillers. This composite structure enhances overall material compatibility and uniformity, ensuring stable performance while achieving flame retardancy
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 solution provides cables and wires with improved flame retardancy, superior abrasion resistance, and enhanced processing properties, passing stringent tests such as the single wire burning test and dripping behavior, while being free from halogen-containing compounds and suitable for industrial-scale production.
Implementation Method 1
the flame retardancy of such compositions is based on synergistic effects between these three components which in case of burning lead to the formation of a physically and firmly stable char layer that protects the polymer from further burning
Implementation Method 2
an organic polymer matrix typically comprising an acrylate or acetate
Data Source
AI summary
The present invention in a first embodiment relates to a conduit or automotive wire consisting of an inner conductor core surrounded by a flame retardant layer made of a polymer composition in a continuous process which composition comprises (A) an olefin homo- and/or copolymer, (B) a silicone-group containing compound, and (C) an inorganic filler, wherein the ratio of the MFR2 measured under a load of 2.16 kg and at a temperature of 190° C. of component (A) to the MFR2 measured under a load of 2.16 kg and at a temperature of 190° C. of the composition is higher than 3.5, and the wire has a length of at least 100 m. In a second embodiment, the present invention relates to a power or communications cable or wire comprising a flame retardant layer made of a polymer composition comprising (A) an olefin homo- and/or copolymer, (B) a silicone-group containing compound, and (C) an inorganic filler, wherein the ratio of the MFR2 measured under a load of 2.16 kg and at a temperature of 190° C. of component (A) to the MFR2 measured under a load of 2.16 kg and at a temperature of 190° C. of the composition is higher than 3.5, the cable or wire further comprising at least one further layer.