Flame retardant Polymeric Materials. 1. Flammability standards & environmental safety regulations

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1 Nippon Gomu Kyokaishi, No. 7, 2013, pp Flame retardant Polymeric Materials. 1. Flammability standards & environmental safety regulations H.M. Nishizawa Nishizawa Technical Laboratory, Kami-Iidamachi, Izumi-ku, Yokohama , Japan Selected from International Polymer Science and Technology, 40, No. 11, 2013, reference NG 13/07/234; transl. serial no Translated by K. Halpin INTRODUCTION Polymer materials have become increasingly important throughout industry, where they are playing an active role as various functional materials are developed. However, polymer materials have the drawback of flamm ability and flame retardancy standards have accordingly been laid down. Flame retardancy standards take many forms, from those of global currency to country-specific standards, though with recent progress in international harmonisation, the UL standards, IEC standards and Japan s Product Safety and Electrical Appliance and Materials (PTE) Law have been harmonised and a mutual recognition system now operates. For flame retardants too, the worldwide problem of the safety of chemicals is being addressed with particular reference to bromine based flame retardants, and inter national integration under the RoHS and REACH regulations has led to a clarification of the once confused position regarding environmental safety. Flame retardant polymer materials are being developed and deployed in wide-ranging applications in key areas including the electrical and electronic, construction, automotive, rolling stock and textile industries. The present series of five reviews examines the historical development and current status of flammability standards, advances in flame retardancy mechanism, flame retardant technology, types and usage of flame retardants, and flame retardant products of recent interest, and seeks to identify future directions of development. Flame retardancy and environmental safety controls past and present The connection between mankind and fire originates in remote antiquity. The course of human evolution would have been intimately bound up with fire because of the need for healthy meals or to heat dwellings at times of severe cold. Fires, on the other hand, have created serious problems. Numerous old records of fires have been preserved in Europe, including the loss of 13,200 households in London in the 1600s, the great fire of Moscow in 1812, and the loss of 4,200 buildings in the great fire of Hamburg in While a primitive method of flameproofing by coating with pulverised earth had been in use since ancient times, the technique of coating with a paint of clay or plaster was introduced in the 1600s. The first patented flame retardant, proposed in 1735 in England, is said to have been a composition of alum, borate compounds, and sulphate salts as a fire-proofing paint for cotton cloth and paper. The APP (ammonium polyphosphate), aluminium chloride and zinc borate still in use today made their first appearance as flame retardants in Before considering flame retardancy, mention should be made of some of the recent fire statistics for Japan and the world. According to statistics for 2012, the number of fires in Japan totalled 44,102, with 1,720 fatalities and 6,860 injured; as shown in Table 1 and Figure 1, the cause of fire in order of decreasing frequency was arson, cigarettes, and bonfires, with electrical fires taking seventh place [1]. The unexpectedly low number of elec trical fires is 2014 Smithers Rapra Technology T/5

2 Table 1. Comparison of number of fires, fatalities, etc, recorded in 2011 and 2012 Statistic Change on previous year Total number of fires 50,000 44,102 12% Building fires (of which house fires) 26,795 (14,974) 25,525 (14,108) Vehicle fires 5,129 4, Forest fires 2,093 1, Maritime fires Aircraft fires Other fires 15,895 12, Deaths due to fires 1,766 1,720 3 (number injured) (7,286) (6,806) 7 Deaths due to house fires 1,070 1,017 5 ((fatalities of age 65 upward) (711) (677) ( 5) Number of fires by cause Arson 5,832 5,340 5 Cigarette 4,762 4, Bonfire 3,443 2, Suspected arson 3,931 3, Hob/hotplate 4,178 3,941 6 Arson plus suspected arson 9,563 6, ( 6) Figure 1. Break-down of cause of fire for fires in Japan in [clockwise from top right]arson 5,340 12%, Cigarette 4,192 10%, Hob/hotplate 3,941 9%, Suspected arson 3,184 7%, Bonfire 2,425 6%, Stove 1,536 3%, Lighting/telephone wiring 1,375 3%, Other causes 16,635 38%, Unknown/under investigation 5,474 12% characteristic. To identify differences between fires in Japan and other major nations, the fire-fighting statistics for key conurbations around the world can be compared by reference to Table 2 [2]. In comparison with Tokyo, electrical fires or fires due to cooking equipment now rank first in many cities. To combat fire hazard, flame retardancy standards have been introduced worldwide for most fields of industry. Table 3 lists the flame retardancy properties and test methods required for key products under Japanese standards [3]. The information presented is for electrical and electronic equipment, buildings, motor vehicles, ships, textiles, aircraft and furniture and furnishings; only the key points of the flame retardancy standards are listed here and the standards themselves should be consulted for detailed information. The important items here are the evaluative tests. So many different tests are prescribed by the standards that there is only space to review two of these: the cone calorimeter test, which holds a key position in the most recent ISO, AST, and JIS standards, and the UL94 vertical burn flammability test adopted worldwide as a standard test for flame retardancy. Details are given in Figure 2, Photograph 1 [4], Figure 3 and Table 4 [5]. The cone calorimeter in particular tracks the rate of heat release while also allowing the smoke density, carbon dioxide and carbon monoxide emissions, and combustion residue, to be tracked automatically, recorded and printed out. Many investiga tors have accordingly used this as an evaluative test in recent research on flame retardancy technology. The UL94 vertical burn test shown in Figure 3 has been adopted globally as a basic combustion test particularly for electrical and electronic equipment. It includes an evaluation of the intensity of burn due to the vertical orientation, glow in the later stages of combustion, and dripping. A limiting oxygen index of 30 must be cleared to qualify for the V-0 grade investigators generally set as the target for development. An inherent problem is T/6 International Polymer Science and Technology, Vol. 41, No. 1, 2014

(second most common) Cause of fire (third most common) Hong Kong 690 4,697 438 2,949 8,084 Cooker heat Cigarette Arson?

arson Technical faults Berlin 340 - - - 8,233 - - - Avon 102 1,564 1,685 3,365 6,504 Not known Naked flame Cooking Edmonton 73 1,505 402 1,688 3,595 Arson Not known Component failure, breakage

3 Table 2. Fire statistics for major conurbations around the world (2006) Conurbation Population ( 10,000) Building fires Vehicle fires Forest fires, etc Total fires Cause of fire (most common) Cause of fire (second most common) Cause of fire (third most common) Hong Kong 690 4, ,949 8,084 Cooker heat Cigarette Arson? Seoul , ,954 Electrical Cigarette Arson Taipei Electrical Arson Cigarette Vienna , Paris 620 4,568 5,125 5,125 18,793 Not known Suspected arson Technical faults Berlin , Avon 102 1,564 1,685 3,365 6,504 Not known Naked flame Cooking Edmonton 73 1, ,688 3,595 Arson Not known Component failure, breakage Montreal 185 1, ,516 10,703 Smoking articles - Naked flame cooking Boston 59 2, ,406 4,947 Unintentional Not known Appliance fault, heat source Los Angeles 411 2,691 2,511 5,131 10,333 Arc discharge Radiation, heat conduction San Francisco ,162 3,969 Electrical appliance heat Tokyo 1,212 3, ,655 5,916 Arson, suspected arson Cigarette Cigarette Electrical appliance heat Naked flame Gas cooktop Figure 2. System block diagram for the cone calorimeter test (heat release test) used in many standards and in recent research Photograph 1. Conical heater for cone calorimeter (heat release test) Figure 3. Sample configuration for UL94 vertical burn test 2014 Smithers Rapra Technology T/7

4 Table 3. Main flame retardancy standards and properties required in Japan and internationally in different fields of industry Products field Flame retardancy standards and flame retardancy properties required Flame retardancy technology applicable, etc Electrical and electronic equipment Electric wire and cable Electrical Appliances & Materials Safety Law (Japan) Mutual harmonisation of IEC standard (IEC60950), UL standards and ISO, publication of Product Safety Electric Appliance and Materials Mark (PSE), introduction of test methods such as UL94. JIS Standards Introduction of IEC and ISO standards, UL94 and allied testing UL Standards Various UL standards and test methods laid down for household electrical products, electronic equipment and IT equipment. UL746 A, B, C, D: Evaluation of properties of polymer materials and processed goods UL746E: Polymer materials, printed circuit boards, etc UL1270: Acoustic equipment UL1270: TV UL94 Combustion testing of polymer materials Requirements UL94V, HB, V-2, V-3, 5VA, 5VB equivalence required depending on type of product EM Electric Wire & Cable Standard (non-halogen flame retardancy) (1) JIS C 3005, 60 test (Self extinction in <60 sec) (2) Smoke emission (Relative optical density <150) (3) Acidity of evolved gas (Absorbent liquid ph >3.5) Nuclear power cable (1) Oxygen index: insulation >25, sheath >27. (2) IOCA test compliance (credible emergency performance) Radiation exposure, thermal degradation, hot steam resistance ageing tests (3) Smoke emission Relative optical density <150 Group cable combustion test (JIS C 3521, etc) Vertical tray test, self-extinction, burn length, flaming combustion and glowing combustion evaluation Buildings Building Standards Law (Japan) Noncombustible materials (No damage or noxious gas after 20 min burn) Timber itself is regarded noncombustible if test compliant. Semi-combustible materials (No damage or noxious gas after 10 min burn) (No damage or noxious gas after 5 min burn) Test methods and specifications For noncombustible materials the ISO heat release test (cone calorimeter) and the ISO 1182 incombustibility test are performed For semi-combustible materials the ISO WD revised scale model test is performed For flame retardant materials the heat release test and revised scale model test are performed Heat release specifications - maximum rate <250 kw/m 2 - total heat released <8 MJ Fire-retardant woods for buildings (JIS A 5801) Class 1-3 for interiors, Class 1-2 for exteriors, evaluated as level of damage when tested by JIS A Fire-retardant construction materials (JIS A K 5661) Types 1-3 compliant products (under JIS A 1321 Test method) Evolved gas toxicity test (JIS A 1321) The time to cessation of movement in 8 mice is observed, and compared with combustion gas from lauan wood. The compliance criterion is a time to cessation of movement of not less than 6.8 min. Flame retardant systems * Bromine based + Sb trioxide + phosphorus compounds, Use of a wide range of systems such as intumescent (surface expansion) flame retardants, phosphinates, hydrated metal compounds etc. Recently increased use of condensed phosphate ester systems. * Proscribed flame retardants clarified through application of WEEE and RoHS controls (PBB, PBDE). used Numerous, including PO, various engineering plastics, thermoset resins, synthetic rubber. Flame retardant systems Mg hydroxide + auxiliary (auxiliary: red phosphorus, silicone, zinc borate, condensed phosphate ester, etc) Bromine based + Sb trioxide Phosphorus compounds used PE, crosslinked PE, PVC, synthetic rubber, fluororesins, silicone rubber Flame retardant systems All flame retardant systems used: halogen based, phosphorus based, inorganic, nitrogen based, others. used PE, PVC, PP, Various general purpose engineering plastics, Synthetic rubber, PUR Flame-retardant paper, EVA latex, Timber, Various textiles T/8 International Polymer Science and Technology, Vol. 41, No. 1, 2014

5 Table 3. Cont'd... Products field Flame retardancy standards and flame retardancy properties required Flame retardancy technology applicable, etc Motor vehicles JIS D 1201 (Road vehicles, and tractors and machinery for agriculture and forestry -- Determination of burning behaviour of interior materials) (1) Horizontal burn test (2) Combustibility assessment specifications All 5 specimens must meet any of the following criteria: 1) Incombustibility 2) The rate of burn does not exceed a maximum of 100 mm/min 3) Burning ceases within 60 sec of reaching the A calibration line and the length of burn thereafter is less than 50 mm. FMVSS 302 Motor Vehicle Safety Standard, Interior materials flammability test (USA, etc) Standard forming the basis of JIS D 1201 and used worldwide. Content as JIS D Railway rolling stock Ministry of Land, Infrastructure, Transport & Tourism (MLIT) Ordinance, Article 83 (as amended 2005) [Japan] (1) An alcohol lamp and B5 size rectangular sample are set at an angle of 45, the centre of the sample is burned, and the time to extinction, flame combustion and glow combustion are evaluated. (2) A heat release test is carried out by cone calorimeter following ISO 5660; the total heat release, ignition time and maximum heat release rate are specified. Specification (2 stage evaluation) Total heat release <8 MJ/m MJ/m 2 Ignition time - >80 sec Maximum rate <300 <300 Ships Ship Fire Protection Structure Regulations (MLIT) Combustion tests ISO II-2, ISO TC92 and TC61 Standards (1) Flame transmission test (ISO A653 XV1, ISO ) Observation Floor surfacing Primary deck covering Total heat released MJ <1.5 <1.5 Maximum rate of combustion heat release kw <10.0 <10.0 Formation of burning droplets None Flame retardant systems All systems used including bromine-based, phosphorusbased, inorganic, nitrogen-based. PVC, PO, PU foam Synthetic rubber, rubber asphalt (rubber asphalt based water-proof coating material) TPE, textiles Flame retardant systems All systems used including bromine-based, phosphorusbased, inorganic, nitrogen-based. General purpose resins, engineering plastics Synthetic rubber, thermosetting resins, etc. Flame retardants Phosphorus compounds, inorganic compounds, intumescent systems, etc. Epoxy resin, synthetic rubber, PET, acrylic resin, engineering plastics, PO, etc. (2) Smoke emission (Dm) Bulkheads, ceiling surface <200, floor surface, primary deck <400 (3) Noxious gases (below specified concentration) CO, CO 2, HCl, HBr, HF, HCN, NO 2, etc (4) Heat release rate (ceilings, bulkheads, surfacings <45 MJ/m 2 ) 2014 Smithers Rapra Technology T/9

6 Table 3. Cont'd... Products field Flame retardancy standards and flame retardancy properties required Flame retardancy technology applicable, etc Textiles JIS L 1091 Tests are categorised as methods A, B, C and D; tests before and after washing are by methods F2 and D of JIS L 1042; dry cleaning is tested by JIS L Extinction specifications (under Japan Fire Protection Association designated test methods) Textile Observation Standard (thick fabric, thin fabric) Non-melting fabrics Flame combustion time Glow combustion time Area charred Melting fabrics Length charred Flame contact time Plywood Fibreboard Flame combustion time Glow combustion time Area charred Carpet Flame combustion time Length charred 3 sec 5 sec 5 sec 20 sec 30 cm 2, 40 cm 2 30 cm 3 times 10 sec 30 sec 50 cm 2 20 sec 10 cm Flame retardants Bromine-based, phosphorus-based, nitrogen-based, inorganic flame retardants Cotton, wool, PVOH, PA, PET, acrylics, Rayon, PVC, PP Meta-aramid resin, melamine resin Others Aircraft Furniture and furnishings U.S. FAR standard The flame retardancy standard applies to indoor equipment materials. Test methods use EAR, Part 25, vertical, horizontal, 45 and 60 tests Properties evaluated Self-extinguishing properties, burn length, combustion time Dripping, heat release, smoke emission Upholstered furniture Fire Protection Association specifications apply in Japan. Detailed standards for mattress flammability operate in the European countries. Flame retardants All flame retardants are used as appropriate Fluoro-resins, engineering plastic resins Flame retardants All types of flame retardant used PU, PA, PET, cotton, wood, engineering plastics, etc T/10 International Polymer Science and Technology, Vol. 41, No. 1, 2014

7 Table 4. Flame retardancy class under UL 94 vertical burn criteria Criterion V-0 V-1 V-2 Flaming combustion time of individual specimens (t 1 or t 2 ) <10 sec <30 sec <30 sec Total flaming combustion time of set of specimens for the given conditioning <50 sec <250 sec <250 sec conditions (t 1 +t 2 for 5 specimens) Sum of flaming combustion time and glowing combustion time for individual <30 sec <60 sec <60 sec specimens after the second flame application (t 1 +t 3 ) Flaming combustion or glowing combustion extending to clamp None None None Ignition of cotton wool due to burning or dripped matter None None Ignites the need for a certain amount of qualitative judgement in assessing the time to self extinction and susceptibility to dripping, and key points in test management are to raise precision by controlling the time for which the material being tested is left to stand before the test, and the environment in which the material stands (the temperature and humidity). Other techniques recently used for compositional analyses, quantitation and mechanistic analysis in studies of flame retardancy mechanism include TGA, SEM, DTA, FR-IR, NMR, X-ray microanalysis, gas chromatography, high speed VTR and DVD. Flame retardancy standards for rubber products include standards for belts (JIS K6324), electric wire and cable (JIS C3665, nuclear power cable standards and specifica tions IEEE ), polyurethane foam (JIS A9511, Japan Flame Retardant Association furniture and furnishing specifications), vibration isolator materials for ships (MLIT structural fire protection regulations), sealant materials for through-penetration firestopping structures in buildings (cableway firestop regulations), and automotive interior seats and vibration isolators (FMVSS No. 302, JIS D1202, ISO 3795). Figure 4 shows the test method for belts, the oldest of the tests for rubber products. Among recent trends meriting attention is the growing demand for rubber products compliant with controls on smoke emission and toxic gas emission for products used in underpasses and underground railways. Although the flame retardancy targeted by developers of materials compliant with the flame retardancy standards listed in Table 3 differs with the product, class of component, and site of use, the usual goal is compliance with V-0 in UL94. This targets a limiting oxygen index of not less than about 30, which gives a provisional benchmark for rate of heat release of not more than 200 kw/ m 2 under the test conditions stipulated in the Building Standards Law. Table 5 and Figures 5-7 show the sites at which flame retardant components are used, along with the polymer materials and flame retardant grades, for some leading products, namely copiers, electrical wires and cables, motor vehicles and rolling stock [6]. Figure 4. JIS K6324 Combustion test apparatus for rubber belt A consistent topic of discussion in relation to flame retardants over the last two decades has been the question of environmental safety. The safety of bromine based flame retardants became problematic in the latter half of the 1980s, giving rise to the ecolabel movement, principally in Germany in the EU and in Scandinavia (Norway and Sweden). This was prompted by the disclosure by researchers at the Swiss Federal Laboratories that dioxins are evolved when flame retardant resins burn. A consensus that bromine flame retardants contained in the resins were hazardous then developed, leading to introduction of the BAM (Blue Angel Mark) in Germany, TCO (Confederation of Professional Employees) certification in Sweden, and White Swan ecolabeling in Norway. Dioxin emission by PVC was also questioned, and the impact the dioxin question has had over the last ten years is well known. Introduction of the RoHS controls in July 2006 effectively halted manufacture of the decabromide series RoHS-designated brominated flame retardants PBB (poly bromodiphenyl) and pentaand octa- PBDE (polybromo diphenyl ether), and was followed by a ban on deca-pbde. This has preserved some semblance of calm over the environmental problem posed by flame retardants. With the pre-registration stage complete, REACH controls are now being rolled out. As to RoHS, extension of an expanded RoHS to hitherto 2014 Smithers Rapra Technology T/11

8 Table 5. Site of application of flame retardant materials and flame retardancy levels in typical applications Product, field Site of application of flame retardant materials and flame retardancy levels Applicable standards Copiers Basically, all moulded resins must have high flame retardancy Exposed type exterior plastics (UL94 vertical > IIB) Switch buttons, knobs, nameplates Exterior plastics (enclosures of all kinds) Fire-resistant type (>5V), mechanical reinforcement plastics (>HB) Internal plastics (fire-resistant enclosures) Near an ignition source (>V0), elsewhere (>V1) Fire-resistant enclosures (internal plastic) Inner cover, duct, housing, etc (>V2) Parts in close proximity to high voltage (V2) Polymers used are ABS, modified PPE, PC/ABS, PC, PC alloy, PET. Flame retardancy: compliance with above UL grades, as oxygen index. Electric wire and cable Power cords 600V cabtyre cable 600V insulated cable Equipment leads Compliance with UL (VW-1) vertical test Polymers used are CR, CSM, PVC flame retardant PO. Flame retardancy: as oxygen index. Motor vehicles ISO 3795 (Flammability of interior materials) Road Transport Vehicle Safety Standards, Article 20, Para. 2. Compliance with horizontal burn test specifications Polymers used include synthetic rubber (EPDM, TPE), PO, PVC, engineering plastics, textiles. Level of flame retardancy: as oxygen index. Rolling stock JR Rail Transport Notice No. 83, Flame retardancy standard for rolling stock materials, Ignition, flammability, smoke emission, charring, deformation, glow combustion Total heat release <8 MJ/m 2, 8-30 kw/m 2 Polymers used are various synthetic rubbers, engineering plastics, general purpose resins, etc. Flame retardancy: as oxygen index. Heat release rate: complies with standard. * METI Ordinance under The Electrical Appliances & Materials Law - Safety of IT Equipment (IEC 60950) * UL94 Vertical burn test (For information) See Figure 6 for flame retardant classification of internal parts of apparatus JIS C 3301 JIS C 3527 JIS C 3621 UL1581, UL83 Test methods JIS C 3005 UL1581 JIS D 1201 FMV SS302 See Figure 6 for flame retardant parts within vehicles 7) Updated as Ministry of Land, Infrastructure, Transport & Tourism (MLIT) Ordinance No. 83, Fire protection measures for rolling stock (2005) See Figure 7 for flame retardant items for rolling stock 8). T/12 International Polymer Science and Technology, Vol. 41, No. 1, 2014

9 Figure 5. Siting of constituent parts of a copier in relation to flame retardancy grade Figure 6. Site and nomenclature of automotive parts targeted for flame retardancy. (1) seats, (2) seatbelt, (3) rooflining, (4) convertible top, (5) arm rest, (6) door trim, (7) front trim, (8) rear trim, (9) side trim, (10) rear luggage shelf, (11) head restraint, (12) carpet, (13) mat, (14) sun visor, (15) sunshade, (16) wheel housing cover, (17) engine compartment cover, (18) mattress cover, (19) instrument panel pad, (20) steering centre pad, (21) airbag, (22) knee bolster Figure 7. Materials used in rolling stock at sites targeted for flame retardancy 2014 Smithers Rapra Technology T/13

10 excluded medical equipment and control equipment is expected in 2014 and For the past six years or so the health risk of phosphorus based flame retardants, primarily phosphate esters, has been a concern, and a risk assessment has been made by the Japan Flame Retardant Association, which reported that the risk is extremely low. While the environmental safety of flame retardants has thus become much better defined, a tendency has emerged for manufacturers to anticipate safety issues and use heat-resistant, high molecular weight types of low degradability. Conclusions As the first of a series of five keynote reviews, this article has set out the background to the development and application of flame retardant polymer materials with reference mainly to flame retardancy regulation and environmental safety controls. The second review in the series will look mainly at the mechanism of polymer flame retardancy. References 1. /neuter topics / houdou/ h25 /250417_1houdou/01houdoushiryou.pdf html/ks html 3. Nishizawa H., Korede Wakaru Nannenka Gijutsu, Koygyo Chosakai, Tokyo, (2003). 4. Toyoseiki Seisakusyo, The Cone Calrimeter Techical Report, (2003). 5. Inui Y., In 'Nannenzai Katsuyo Binran', Nishizawa H., Takeda K. Eds., Technonet, Tokyo, (2002). 6. Nishizawa H., Atarashii Nannenzai, Nannennka Gijutsu, Gijutsu Joho Kyokai, Tokyo, (2008). 7. Ishibasi T., In 'Kasai Binran 3rd Ed.', Nippon Kasai Gakkai, Ed., Kyoritsu Shuppan, Tokyo, (1997). 8. Nishizawa H., Plastics Age, 55(5), 9 (2009). T/14 International Polymer Science and Technology, Vol. 41, No. 1, 2014

EU flammability standards and ENFIRO

EU flammability standards and ENFIRO Pim Leonards Institute for Environmental Studies, VU University Amsterdam Email: pim.leonards@vu.nl EU research project FP7: 226563 Life Cycle Assessment of Environment-Compatible