Flame-Retarded Foamed Polystyrene Composition with Brominated Additives
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Solution Overview
Problem
Foamed polystyrene materials face challenges in achieving adequate flame retardancy while maintaining mechanical strength and thermal stability, as existing brominated flame retardants are thermally unstable and require high concentrations that compromise other properties, and alternative flame retardants often require additional heat stabilizers that either degrade the resin or reduce flame retardancy.
Innovation Solution
A flame-retarded foamed polystyrene composition comprising a brominated flame retardant with a bromine content greater than 60% and a 5 wt % loss temperature between 190° C. and 320° C., combined with a hindered amine compound, which enhances flame retardancy and thermal stability, allowing for reduced concentrations of the flame retardant and preservation of resin properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the amount of flame retardant is increased to compensate for increased flammability, then flame retardancy is improved, but mechanical strength and bulk density are adversely affected and production cost increases
Solution Approach 1:
The invention changes the chemical composition parameters of the flame retardant system by introducing a synergistic combination of brominated flame retardant and phosphite ester heat stabilizer, rather than simply increasing the amount of single flame retardant. This parameter change allows achieving the same flame retardancy with lower overall additive content, thus preserving mechanical strength.
Solution Approach 2:
The invention creates a composite flame retardant system by combining brominated flame retardant (HBCD or TBCO) with phosphite ester heat stabilizer. This composite approach provides multiple functions: flame retardancy from the brominated compound and thermal stability from the phosphite ester, eliminating the need for high concentrations of single additives that would compromise mechanical properties.
2Reliability
If HBCD or TBCO is used alone in the extrusion foaming process, then flame retardancy is achieved, but discoloration occurs and decomposition products corrode the extruding machine
Solution Approach 1:
The phosphite ester heat stabilizer acts as an intermediary substance that protects the brominated flame retardant from thermal decomposition. It intervenes in the degradation process by forming a protective complex or releasing stabilizing agents that prevent the formation of corrosive HBr and discoloration-causing decomposition products, thus protecting both the foam quality and equipment.
Solution Approach 2:
The invention converts the potential harmful thermal decomposition of brominated flame retardants into a beneficial stable system. By adding phosphite ester heat stabilizer, the decomposition tendency is transformed into a stable complex that maintains flame retardancy while eliminating harmful effects like discoloration and corrosion.
3Stability of the object's composition
If organotin stabilizers are used in combination with other heat stabilizers, then thermal stability is improved, but ecological harm increases
Solution Approach 1:
The invention replaces persistent and ecologically harmful organotin stabilizers with phosphite esters that are more environmentally benign. The phosphite esters perform the necessary thermal stabilization function during processing and then degrade into harmless products, unlike organotins that persist in the environment. This substitution maintains thermal stability while eliminating ecological harm.
4Stability of the object's composition
If isopropylidenediphenyl phosphite compound is used as heat stabilizer, then thermal stability is improved, but hydrolysis susceptibility increases preventing recycling
Solution Approach 1:
The invention changes the chemical structure parameters of the phosphite ester to achieve optimal balance between thermal stability and hydrolytic resistance. By selecting specific phosphite ester structures with appropriate alkyl or aryl groups, the composition achieves sufficient thermal stability during processing while maintaining resistance to hydrolysis, thereby enabling recycling of foam scraps.
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 combination significantly enhances flame retardancy of polystyrene foams, reducing the need for high flame retardant concentrations, maintaining resin properties, and enabling recycling of foam scraps, while achieving desired flame retardancy levels without compromising mechanical strength or thermal stability.
Implementation Method 1
HBCD and TBCO are relatively thermally unstable and their 5 wt % loss temperature are 230-250° C. and 200° C., respectively
Implementation Method 2
the hindered amine compound... enhances flame retardancy and thermal stability
Data Source
AI summary
A flame retarded foamed plastic composition comprises a polystyrene type resin; a brominated flame retardant having a Br content greater than 60% by weight and a 5 wt % loss temperature of 190-320° C.; a hindered amine of 4-hydroxy-2,2,6,6-tetramethylpiperidine carboxylate series, and a blowing agent.