Flame-Retardant Cable Polymer Composition With Halogen-Free Synergy
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Solution Overview
Problem
Existing flame retardant polymer compositions for cable insulation often compromise between mechanical properties and flame retardancy, particularly for thin cables, and may not perform well in fire tests involving cable bundles.
Innovation Solution
A halogen-free flame retardant mixture comprising specific combinations of phosphinic acid salts, telomers, organylphosphonates, phosphite, silicates, and other nitrogen- and phosphorus-containing compounds, which are formulated to enhance both mechanical properties and flame retardancy in thermoplastic elastomer compositions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If halogen-containing flame retardants are used to achieve good flame retardancy, then flame retardancy is improved, but toxic vapors and corrosive combustion gases are generated which are harmful to health and can damage building structures
Solution Approach 1:
The patent converts the harmful effect of halogen-containing flame retardants by replacing them with halogen-free alternatives that generate non-toxic smoke and vapors. The invention uses phosphorus-containing compounds and nitrogen-containing compounds as flame retardants that decompose to form protective char layers and non-toxic gases, thereby eliminating the harmful effects while maintaining flame retardancy.
2Reliability
If metal hydroxides are used as flame retardants to achieve good flame retardancy, then flame retardancy is improved, but the flexibility of polymers is worsened and cables become stiff and sensitive to scratching
Solution Approach 1:
The patent changes the chemical composition parameters by using organic phosphorus-containing compounds and nitrogen-containing compounds instead of inorganic metal hydroxides. This parameter change maintains flame retardancy through chemical intumescence mechanisms while preserving the flexibility and mechanical properties of the polymer matrix.
3Reliability
If large amounts of flame retardants are added to achieve good flame retardancy, then flame retardancy is improved, but mechanical properties and processibility are deteriorated
Solution Approach 1:
The patent creates a composite flame retardant system combining phosphorus-containing compounds and nitrogen-containing compounds that work synergistically. This composite approach achieves effective flame retardancy at lower total concentrations compared to single additives, thereby maintaining mechanical properties and processibility.
4Reliability
If phosphates or polyphosphates are used as flame retardants to achieve good flame retardancy, then flame retardancy is improved, but they show only low effectiveness at relatively low temperatures and have low oxygen index
Solution Approach 1:
The patent modifies the thermal performance parameters by using phosphorus-containing compounds with higher decomposition temperatures and nitrogen-containing compounds that enhance char formation. This combination raises the oxygen index and improves effectiveness at lower temperatures through synergistic intumescence mechanisms.
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 proposed flame retardant mixtures achieve excellent mechanical properties and very good flame retardancy, even after aging, and are effective in challenging fire tests such as the FT-4 vertical tray test, without compromising on mechanical stability or flame retardancy.
Implementation Method 1
In the event of fire, the thick plumes of smoke that arise therefrom can hinder orientation on the escape routes. Moreover, toxic vapors and corrosive combustion gases can arise
Implementation Method 2
If just small amounts of a thermoplastic polymer ignite, the spreading flames can easily cause major damage
Data Source
AI summary
What are described are flame retardant mixtures comprisinga) salt of a phosphinic acid of the formula (I) in which R1 and R2 are independently alkyl, cycloalkyl, aryl or aralkyl that are optionally substituted, M is an m-valent cation, and m is 1 to 4, b) salt of a phosphinic acid of the formula (II) that differs from component a) in which R3 is optionally substituted alkyl, cycloalkyl, cycloalkylalkyl, aryl or aralkyl, preferably with alkyl radicals as substituents, R4 is alkyl with an even number of carbon atoms, with the proviso that, if R1 and/or R2 are alkyl, R4 has twice, three times or four times the number of carbon atoms of R1 or R2, M is an n-valent cation, and n is 1 to 4, c) organylphosphonate,d) phosphite,e) silicate, alumosilicate and/or silicon dioxide which is solid at 25° C.,f) a representative selected from the group of triazine complex, polyphosphate, hypophosphite, nitrogen-containing diphosphate, organophosphate, phosphazene and/or polyphosphonate,g) optionally a representative selected from the group of metal hydroxide, metal carbonate, metal borate, zinc stannate and/or intumescent additive, andh) optionally pigment.The mixtures can be used for production of flame-retardant polymer compositions comprising thermoplastic and elastomeric polymers that are of excellent suitability for production of cable sheaths or cable insulations.