Flame Retarding PVC. Glade E. Squires Sales Manager - Flame Retardants Omya, Inc.

Transcription

1 Flame Retarding PVC Glade E. Squires Sales Manager - Flame Retardants Omya, Inc.

2 Flame Retardants Increase ignition temperature and the time to ignition, and / or material self-extinguishes Prevent Fires From Starting Decreased rate of combustion results in lower heat release to adjacent surfaces and objects Increase Escape Time For Occupants Reduce the rate of fire spread to avoid or delay flashover Increase Response Time 2

3 Fire Triangle Fire is an Oxidation Chemical Reaction between oxygen and fuel, triggered by an ignition source or heat HEAT Break any leg of the triangle and combustion will be suppressed. FIRE 3 FUEL Mixing of fuel and air AIR

4 Flame Retardants Modes of Action Oxygen Gas Phase Flame Combustion Gases Cooling ATH / Mg(OH)2 Volatile Gases (fuel) Free Radicals Halogen / Sb Phosphorus Charring Phosphorus Polymer Decomposition Intumescence Nitrogen 4 Heat Polymer Ignition Source

5 PVC Pure PVC is inherently Flame Retardant 56.8% by weight Chlorine Oxygen Index of 47 5 Difficult to ignite and self-extinguishes As PVC thermally decomposes, HCl evolves HCl suppresses combustion in the flame Chlorine atoms attach to free radicals Double bonds are formed, cross-linking can occur HCl reacts with molten PVC to produce char Char acts as an insulation layer and reduces volatiles (fuel)

6 Flexible PVC As plasticizer is added to soften PVC Chlorine content is reduced Fuel is added Flammability increases in proportion to the amount of plasticizer added During combustion plasticizer volatilizes and becomes fuel, increasing flammability 6

7 Antimony Trioxide - Sb 2 O 3 Flame Retardant Synergist Combines with the Chlorine atoms released during combustion Antimony Trichloride is formed as Antimony and Chlorine combine Attaches Chlorine atoms to free radicals in the flame Chain reaction of combustion is suppressed Fire is extinguished 7

8 Antimony Trioxide - Sb 2 O 3 Strong White Pigment Prior to TiO2 being the most widely used white pigment, Antimony Trioxide was the preferred white pigment Tint strength varies with particle size Choosing the right particle size can reduce tinting and result in pigment savings The larger the particle size, the lower the tint strength 8

9 Antimony Trioxide Powder Grades Powder grades for FR & general purpose applications properties N MT LT Z Average Particle Size µm Sb203 % min sieve refusal (45 µm) sieve refusal (125 µm) 0.1 Impurities Pb ppm max As ppm max Fe ppm max Color stability Transparancy Pigment saving Translucency 9

10 EU Antimony Trioxide Risk Assessment Endpoint Outcome Classification Skin irritation Not irritating Not classified Eye irritation Not irritating Not classified Sensitisation Not sensitising Not classified Acute oral Not acutely toxic via oral route, LD50 > mg/kg Not classified Acute dermal Not acutely toxic via dermal route, LD50 > 8300 mg/kg Not classified Acute inhalation Not acutely toxic via inhalation route, LC50 > 5.2 mg/l Not classified Repeated dose toxicity, oral No systemic toxicity, NOAEL = 1686 mg/kg/day Not classified Mutagenicity Not mutagenic/clastogenic Not classified Reproductive toxicity Not a teratogen Not toxic for reproduction Not classified Carcinogenicity Category 3 via inhalation, local effects, NOAEL=0.51 mg/m³ Category 3 (DSD) Category 2 (CLP) 10

11 Current EU-Regulations By Country Country UK German MAK- Commiss ion Occupational exposure limit (expressed as Sb) 0.5 mg/m³ (as Sb) Not established Maximum exposure time 8h TWA Document number Date Title Second Antimony and edition - compounds Antimony and its inorganic compounds (inhalable fraction) Finland 0.5 mg/m³ 8h TWA 2009 Antimony and its compounds Belgium France Spain 0.5 mg/m³ (as Sb) 0.5 mg/m³ (as Sb) 0.5 mg/m³ (as Sb) Austria 0.1 or 0.3 mg/m³ (as Sb) depending on activity (cfr website) 8h TWA 2010 Antimony and its compounds 8h TWA 2012 Antimony and its compounds 8h TWA 2010 Antimony and antimony compounds 8h TWA 2011 Antimony trioxide Link to the legislation Health and Safety Executivehttp:// Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area /senate/health_hazards/index.html The Ministry of Social Affairs and Healthhttp://pre stm.fi/hm /pass thru.pdf Service public fédéral Emploi, Travail et Concertation socialehttp:// ntent.aspx?id=23914 Institut National de Recherche et de Sécurité - oc/publications.html?refinrs=ed% entacion/textosonline/valores_limite/limites2010 /LEP%202010%20ActualizadoMayo(1).pdf B-D4FB-44D DB2CB1D2078/0/GKV2011.pdf 11

12 U.S. EPA Regulations Are In Line with EU Regulations Results of PBT & vpvb assessment NOT classified as either a PBT or vpvb Inhalation Level < 0.5 mg/m³ exposure limit Transportation Not regulated below 1000 Lbs. Conclusions Focus on worker exposure by way of dust reduction Reduce waste and dust emissions 12

13 Dust Reduction Methods Wetted Antimony Trioxide Powder Reduced dust, enhanced flowability Optimal compatibility with polymer & plasticizer Better utilization of material Reduced loss in packaging Antimony Trioxide Concentrate Pellets Dust-free Ease of conveying Accuate dosing Enhanced dispersion - lower addition levels No loss in packaging 13

14 Antimony Trioxide Powder 14

15 Wetted Powder Significant Dust Reduction 15

16 Dust Level of Various Grades Standard & Wetted 16

17 Dust Versus Plasticizer Level 17

18 Concentrate Dust Free Pellets 18

19 Antimony Trioxide Concentrates Concentrated, up to 90% Active Most Antimony Oxide masterbatches cannot achieve this high a loading Thoroughly dispersed Rapid, thorough dispersion into polymer matrix Dust is eliminated Pellets are homogenous and nonfriable 19 Worker exposure to dust is eliminated Disposal and reporting of Antimony Oxide from dust collection systems is eliminated Complete emptying of packaging No residue or unused material left behind

20 Dust Reduction Methods Wetted Antimony Trioxide Powder Reduced dust, enhanced flowability Optimal compatibility with polymer & plasticizer Better utilization of material Reduced loss in packaging Antimony Trioxide Concentrate Pellets Dust-free Ease of conveying Accuate dosing Enhanced dispersion - lower addition levels No loss in packaging 20

21 Comparison Powder, Wetted, Concentrate 21

22 Potential Savings In Eliminating Packaging Residue 25 Kg Bags 1% remaining = 0.55 pounds per bag 40 bags per pallet = 22 pounds per pallet 20 pallets per truckload = 440 pounds per truckload At $3.00 per pound, $1,300 in savings per truckload 440 pounds of reduced emissions to the environment! 22

23 Alumina Trihydrate Al 2 O 3 3H 2 O Highly Endothermic Decomposition (absorbs heat) Alumina Trihydrate Thermal Decomposition 2Al(OH) 3 Al 2 O 3 + 3H C FR efficiency results from; High Load Levels (less available fuel) Heat absorption during decomposition Release of water Cooling Dilution of oxygen level in flame Dilution of fuel 23

24 Magnesium Hydroxide - Mg(OH) 2 Highly Endothermic Decomposition (absorbs heat) Magnesium Hydroxide Thermal Decomposition Mg(OH) 2 MgO + H C High load levels Rarely below 40% and up to 65% Less polymer (fuel) available FR Efficiency Results from High Load Levels (less fuel) Heat Absorption, more difficult to ignite and support combustion Release of Water, cooling and dilution of flammable gas 24

25 Smoke Suppression As combustion is suppressed smoke is generated as a result of incomplete combustion Zinc Borate Most widely used smoke suppressant Causes charring and cross-linking Reduces afterglow Minor effect from waters of hydration evolving, endothermic reaction and the dilution of fuel Can replace up to ½ of the Antimony Oxide in certain formulations Potential for long-term heat stability to be compromised 25

26 Smoke Suppression Zinc Stannates Zinc Stannate (ZS) - ZnSnO 3 Zinc Hydroxy-Stannate (ZHS) ZnSn(OH) 6 Smoke suppressants and synergists ZHS endothermic reaction as waters of hydration are released, cooling and dilution of oxygen and fuel Low load level, about 3 to 9 phr Can be cost prohibitive for some formulations Some Rigid PVC applications can generate significant amounts of smoke due to other additives such as impact modifiers, processing aids, lubricants and stabilizers Some regulations are requiring smoke reduction for Rigid PVC products used in architectural applications 26

27 Phosphate Ester FR Plasticizers Flame Retardant Secondary Plasticizers Replace a portion of the primary plasticizer while acting as a Flame Retardant Originally Tricresyl Phosphate developed and used Today, Isopropylphenyl Diphenyl Phosphate and Isobutylphenyl Diphenyl Phosphate are used Isobutylphenyl Diphenyl Phosphate considered more sustainable No pigmentation, clarity maintained Relatively good FR efficiency Imparts low temperature stiffness Level needed to achieve FR efficiency based on level of primary plasticizer used 27

28 Phosphate Ester FR Plasticizers Low Temperature Phosphate Esters Alkyl Diaryl Phosphates 2-Ethylhexyl Diphenyl Phosphate Better plasticizer than Triaryls Improved low temperature properties Lower smoke than Triaryls Isodecyl Diphenyl Phosphate Even better low temperature properties Less smoke than the 2-Ethylhexyl Diphenyl Phosphate 28

29 Calcium Carbonate Not a Flame Retardant However; High loadings of finely ground, surface treated Calcium Carbonate Reduce the amount of PVC Concurrently reduces the amount of plasticizer used As a result, flammability is decreased, requiring less Flame Retardant to achieve the desired rating 29

30 Flammability Tests UL-94 HB, V-0, V-1, V-2, 5VA, 5VB HB = Horizontal Burn Test The three vertical ratings, V2, V1 and V0 indicate that the material was tested in a vertical position with two applications of the flame and self-extinguished within a specified time after the ignition source was removed The vertical ratings also indicate whether the test specimen dripped flaming particles that ignited a cotton indicator located below the sample 5VA and 5VB, vertical tests where the flame is applied five times 30

31 Flammability Tests NFPA 701 Flammability test for textiles and films MVSS 302 Flammability requirements for materials in passenger compartments E-84 (Steiner Tunnel) ASTM Method Evaluates the burn behavior of materials that can be used for walls and or ceilings. Large scale test 24 foot sections. Measures flame spread and smoke density 31

32 Flammability Tests Limiting Oxygen Index Minimum concentration of oxygen expressed as volume percent in a mixture of oxygen and nitrogen that just supports flaming combustion of a material initially at room temperature Air is 20.95% Oxygen. Therefore, any material with an LOI less than 20.95% will burn in air and any LOI greater than 20.95% will selfextinguish Rigid PVC s LOI = 47 32

33 Flammability Tests Cone Calorimiter Measures; Heat flux required for ignition Time to ignition Rate of heat release Peak heat release rate Smoke generation Weight loss over time 33

34 Thank You! 34