Crosslinked Flame Retardant Thermoplastic Elastomer Gel
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Solution Overview
Problem
Current sealants and gels used in electrical and electronic devices lack a combination of properties such as high temperature resistance, safety compliance, and effective flame retardancy without increasing hardness or specific gravity, and often contain hazardous halogen-based additives or require large amounts of metal hydroxides, which are not suitable for soft thermoplastic elastomer compositions.
Innovation Solution
A crosslinked flame retardant thermoplastic elastomer gel composition comprising a char catalyst, a char former, a blowing agent, and a maleic anhydride-modified SEBS, combined with a softener oil, which forms a polymer gel that is RoHS compliant and passes the UL-94 test for flame retardancy, while maintaining a soft and elastic consistency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If halogen-based additives are incorporated to provide fire protection, then flame retardancy is improved, but hazardous substances are generated and RoHS compliance is compromised
Solution Approach 1:
The patent converts the harmful effect of flame retardants by replacing hazardous halogen-based additives with non-hazardous alternatives (metal hydroxides, phosphorus-based compounds, nitrogen-based compounds). These alternatives provide the same flame retardancy function without generating corrosive hydrogen halides, thus transforming a harmful substance problem into a beneficial safe flame retardation system that meets RoHS compliance
Solution Approach 2:
The patent changes the chemical composition parameters by specifying non-halogenated flame retardant compounds (metal hydroxides, phosphorus-based, nitrogen-based) and controlling their particle size and distribution. This parameter change maintains flame retardancy while eliminating hazardous substance generation, achieving both fire protection and environmental compliance
2Reliability
If large amounts of metal hydroxides are incorporated to achieve flame retardancy, then fire protection is improved, but specific gravity and hardness increase undesirably
Solution Approach 1:
The patent changes the particle size parameter of metal hydroxides to sub-micron ranges (0.1-10 micrometers), which allows effective flame retardancy at lower loadings. This parameter change reduces the amount of filler needed, thereby preventing excessive increases in hardness and specific gravity while maintaining fire protection
Solution Approach 2:
The patent uses composite material systems combining multiple flame retardant mechanisms (metal hydroxides for endothermic decomposition, phosphorus-based compounds for char formation, nitrogen-based compounds for gas phase radical quenching). This composite approach achieves effective flame retardancy with reduced filler loadings, preventing unwanted hardness increases
3Reliability
If solid particulate fillers are added to flame retard the gel, then fire protection is improved, but the gel hardens and sealing properties deteriorate
Solution Approach 1:
The patent changes the particle size parameter to sub-micron dimensions (0.1-10 micrometers) and controls the total filler loading to 1-30 parts per 100 parts elastomer. This parameter optimization ensures adequate flame retardancy while minimizing the hardening effect, preserving the gel's softness and sealing properties
Solution Approach 2:
The patent applies surface treatment to the particulate fillers to improve their dispersion and interfacial compatibility with the elastomer matrix. This local quality enhancement at the filler-matrix interface prevents excessive hardening while maintaining flame retardancy, preserving the gel's sealing capabilities
4Temperature
If the gel is crosslinked to increase thermal stability and service temperature, then high temperature resistance is improved, but processability and recyclability are reduced
Solution Approach 1:
The patent incorporates flame retardant compounds and crosslinking agents into the elastomer compound before the vulcanization process. This preliminary action ensures that the flame retardancy and crosslinking functions are pre-positioned in the material, allowing for controlled crosslinking that achieves high service temperature while maintaining reasonable processability during manufacturing
Solution Approach 2:
The patent optimizes the crosslinking density parameter by controlling the type and amount of crosslinking agents used. This parameter optimization achieves sufficient thermal stability for high service temperatures while avoiding excessive crosslinking that would eliminate processability and recyclability
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 gel composition achieves high flame retardancy, thermal stability, and safety compliance, allowing it to operate effectively in environments exceeding 70°C, with improved processability and recyclability, and is free from hazardous halogenated substances.
Implementation Method 1
When an intumescent flame retardant material is introduced to flame, some or all of the material will quickly form a char barrier.
Implementation Method 2
The char barrier is typically foamed away from itself. By foaming away, the char barrier blocks oxygen and the ambient flame from reaching the fuel source.
Implementation Method 3
Crosslinked polymers are known to increase thermal stability, toughness, and chemical resistance compared to their base, or uncrosslinked polymers.
Data Source
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AI summary
Crosslinked flame retardant thermoplastic elastomer gels are provided. The crosslinked flame retardant thermoplastic elastomer gels comprise a char catalyst, a char former, a maleic anhydride-modified styrene ethylene/butylene styrene polymer, and a softener oil. Methods are provided of making crosslinked flame retardant thermoplastic elastomer gels.