Non-Hazardous Flame Retardant Synergists for Polymers
Robert Leeuwendal
Chemspec 2018, Cologne
Global Sales to more than
40 countries
Polymer Structure and Flammability
Char formation- model and mechanism
Role of synergists in flame retardant systems
Examples of Flamtard synergist solutions
Conclusions
Content
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40 countries
Polymer Structure
Polyethylene 17 Polypropylene 17 Polymethylmethacrylate 17
Polystyrene 18
Polyvinylchloride 45
Polytetrafluoroethylene 95
and influence on flammability (LOI)
Polycarbonate 26
Polyetheretherketone 38
Polyphenylenesulfide 44
n
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Polymer FR Additives general principles
~Br, ~Cl+
Sb2O3
Al (OH)3
Mg(OH)2
Phosphatebased
Increasing regulatory pressure on chemicals management and performance requirements (i.e. SBI, smoke) cause established flame retardant solutions to be abandoned or adapted to meet new criteria
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Char Formation
Di Blasi and Branca, 2001
Melting / Softening
Intra-molecular X-ing
Pyrolysis
Oxidative Combustion
T
mechanism and model
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Char Formation intumescent system
Intumescent Protective Coating (aquaeous)
Solution Water (30w%)
Binder EVA Copol (14w%)
Acidic Source Ammonium polyphosphate (25w%)
Carbon Source Penta ehrytritol (15w%)
Spumific or blowing agent Melamine (16w%)
Ratio and concentration of additives determines:
Expansion factor
Number of foam cells
Strength of foam
Percentage charring
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Degradation Model
Di Blasi and Branca, 2001
Problem with Polymer Char:Keeps burning or smoldering if mass and heat transfer are not eliminated
Approach: Build improved char structures and charring mechanisms
How: Use of synergists
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Flamtard Synergists for PVC and halogenfree flame retardant systems
Synergist Flamtard H Flamtard S Flamtard V
Chemical nature Zinc tin oxide Zinc tin oxide Metal doped silicate
Function Promotes X-linking Promotes X-linking High temperature flux
Particle size 1-2 micron 1-2 micron 4-6 micron
Polymer processing < 2200C > 2200C………. > 2200C………..
Benefits in PVCLow smoke, (partially) replaces Sb2O3
Low smoke, (partially) replaces Sb2O3
Partially replaces Sb2O3
Benefits in HFFR materialsImproved char strength and consistency with P flame retardants
Improved char strength and consistency with P flame retardants
Improved char strength and consistency
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Polyurethane Foam
Component (phr) PUR PUR/AAP PUR/ZHS PUR/AAP/ZHS
PU Silpak 200 A + B 100 85 95 80
Alkyl aryl phosphate/phosphonate 15 15
Zinc hydroxy stannate 5 5
Cone Calorimeter @ 35 k/m2
Peak rate of Heat Release (kW/m2) 1079 834 1033 619
Time of Peak RHR (s) 75 76 85 81
Avg heat Release Rate (kW/m2) 349 327 373 294
Total Heat Released (MJ/m2/g) 58.8 49.3 62.1 47.7
Avg Mass Loss Rate (g/m2s) 21.4 21.8 22.8 16.6
Mass Residue (w%) 7.7 5.9 4.5 9.7
Feng Yang, Gordon Nelson, Florida Institute of Technology, Melbourne, FL 32901
synergism with zinc hydroxy stannate
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Polyurethane Foam char analysis after cone calorimeter burning
Feng Yang, Gordon Nelson, Florida Institute of Technology, Melbourne, FL 32901
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40 countries
Polyamide Engineering Plastic
Horrocks, Polymer Degradation and Stability, 104, (2014), 95-103
synergism with zinc stannate
Component (phr) 1 2 3 4 5 6 7 8 9
PA6T/66 (Vestamid HT) 55 55 55 55 55 55 55 55 55
Glass fiber ( 30 30 30 30 30 30 30 30 30
Alumina di-ethyl phosphinate 7.5 0 15 0 0 7.5 15 11.25 3.75
Zinc stannate 7.5 15 0 15 15 7.5 0 3.75 11.25
Polymer formulations were evaluated on flame retardant properties by UL94VB, 0.8 mm and in tested for rate of heat release, smoke formation in the Cone Calorimeter.
Burned test specimen were analysed for char content and morphology.
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Polyamide Engineering Plastic
Horrocks, Polymer Degradation and Stability, 104, (2014), 95-103
synergism with zinc stannate
Global Sales to more than
40 countries
Polyamide Engineering Plastic
Horrocks, Polymer Degradation and Stability, 104, (2014), 95-103
synergism with zinc stannate
PA6T/66 Flamtard S(85/15)
PA6T/66 AliP Flamtard S(85/7.5/7.5)
PA6T/66 AliP Flamtard S(85/15/0)
Test Specimen Residues after Cone Calorimeter Experiment 50kW/m2 heat flux
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40 countries
Polyamide Engineering Plastic
Horrocks, Polymer Degradation and Stability, 104, (2014), 95-103
synergism with zinc stannate
Global Sales to more than
40 countries
Examples Silicon Elastomer synergism with low melting glass
Mechanical strength of chars after burning silicon polymer – mica compounds
Investigation of the ceramifying process of modified silicone silicate compositions, Mansouri, Burford, J. Mater. Sci., Aug 2007
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Conclusions
Flamtard synergists are used at low loadings to improve:
a. Char formation in PVC and phosphate based FR polymer materials, leading to lower smoke and rate of heat release (Flamtard H, S)
b. Barrier properties of char by filling micro cracks, voids, and andbuild viscosity in the decomposition zone, leading to improved flame retardant mechanisms (Flamtard V)
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