Phosphorus Flame Retardants for Textiles. Novecare 18/06/2006 CHALLENGING BOUNDARIES

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1 Phosphorus Flame Retardants for Textiles

2 Summary Introduction How Do Textiles Burn? The Action of a Phosphorus Flame Retardant Flame Retardant Selection Classification of Textile Flame Retardants Inherent Flame Retardant Fibres Methods of Application Flammability Standards and Testing HSE Considerations Conclusions

3 Introduction Flame retardants are prevalent in many aspects of our lives In upholstered furniture Curtaining Car seating Stenter The work place Transportation Winch Dyeing machine

4 How Do Textiles Burn? Textile (fuel) Ignition source Fire + + Oxygen =

5 How Do Textiles Burn? Cellulose decomposes (in oxygen) to tarry depolymerization products, notably levoglucosan Stenter Then to volatile combustible products such as alcohols, aldehydes, ketones and hydrocarbons Flammable gases ignite After flaming, the carbonised residue slowly oxidises (smoulders) until it has been consumed Winch Dyeing machine

6 How Do Textiles Burn? Thermal degradation of Cellulose O CH 2 OH O OH OH O OH OH O CH 2 OH O C HO CH 2 O O OH OH Levoglucosan

7 Summary Introduction How Do Textiles Burn? The Action of a Phosphorus Flame Retardant Flame Retardant Selection Classification of Textile Flame Retardants Inherent Flame Retardant Fibres Methods of Application Flammability Standards and Testing HSE Considerations Conclusions

8 The Action of a Phosphorus Flame Retardant There are Potentially Four ways of Disrupting Combustion Removal of heat or application of cooling. Achieved by treating the material with heat absorbing materials. Increase in pyrolysis temperature i.e. glass fibre, aramids, carbon fibres Elimination of oxygen from combustion zone i.e. halogens Prevent evaporation i.e. form char - Phosphorus

9 The Action of a Phosphorus Flame Retardant Stenter Application of ignition source Formation of phosphorus pentoxide and phosphoric acid Dehydration of cellulose occurs Dehydration reduces the temperature of decomposition ( C as opposed to 375 C for untreated cotton) Evolution of levoglucosan inhibited Flammable tars and gases reduced, char increased Formation of protective layer of char Winch Dyeing machine

10 The Action of a Phosphorus Flame Retardant Synergistic Effect of Nitrogen Nitrogen catalyzes the cellulose phosphorylation The retention of phosphorus in the char may be aided by nitrogen Release of nitrogen gas which dilutes the flammable gases and reduces flaming Higher levels of nitrogen may allow lower levels of phosphorus in the flame retardant

11 Summary Introduction How Do Textiles Burn? The Action of a Phosphorus Flame Retardant Flame Retardant Selection Classification of Textile Flame Retardants Inherent Flame Retardant Fibres Methods of Application Flammability Standards and Testing HSE Considerations Conclusions

12 Flame Retardant Selection Application Application method Performance requirements Fabric composition Fabric construction, weight Fabric must still behave like untreated material COST

13 Summary Introduction How Do Textiles Burn? The Action of a Phosphorus Flame Retardant Flame Retardant Selection Classification of Textile Flame Retardants Inherent Flame Retardant Fibres Methods of Application Flammability Standards and Testing HSE Considerations Conclusions

14 Classification of Textile Flame Retardants Phosphorus containing flame retardants Phosphate Phosphonium Phosphonate R 1 O O P OR 3 OR 2 R 2 R 1 P R 4 R 3 O O R 2 P O R 1 R 3 O O R 2 P O R 1 R 3 Cyclic

15 Classification of Textile Flame Retardants Another method of classifying textile FRs is according to their durability to washing: Durable Resistant to 50 or more washes Semi-Durable Resistant to a water soak Non-Durable Resistant to no washing

16 Classification of Textile Flame Retardants Durable Flame Retardants (Top Treatments) Dialkylphosphonopropionamide Co-reacted with an amino resin and an acid curing catalyst Pad, dry, heat cure followed by alkali wash H 2 C CHCONH 2 + (CH 3 O) 2 P O H O (CH 3 O) 2 P O CH 2 CH 2 CNH 2 HCHO (CH 3 O) 2 P O O CH 2 CH 2 CNHCH 2 OH

17 Classification of Textile Flame Retardants Durable Flame Retardants (Top Treatments) Tetrakis(hydroxymethyl)phosphonium chloride marketed under the PROBAN trademark by Rhodia and is available only under licence Applied to cotton and cotton synthetic blends by pad, dry, ammonia cure and hydrogen peroxide oxidation Durable to repeated washing CL - O CL - (HOCH 2 ) 3 P + CH 2 NHCNHCH 2 P + (CH 2 OH) 3 NH 3 O NHCH 2 PCH 2 NHCNHCH 2 PCH 2 NH CH 2 NH CH 2 O CH 2 NH CH 2 NHCH 2 PCH 2 NHCNHCH 2 PCH 2 NH O O 2 H 2 C P CH 2 CH 2

18 Classification of Textile Flame Retardants Flame Retardants for Polyester fabrics (Top Treatments) Cyclic Phosphonate Ester based products may be used Applied by pad, dry, heat cure process Durable to washing Phosphorus FR s lower the melting point of polyester fabrics allowing the fabric to melt away from the ignition source more easily O H 3 CP O C CH 3 O O x P CH 3 OCH 3 2-x

19 Classification of Textile Flame Retardants Non-Durable Flame Retardants (Top Treatments) Non-durable APP s used End-uses include furnishings, filter fabrics, disposable protective clothing (NH 4.PO 3 )n (HPO 3 )n + nnh 3 Degradation of APP H 3 PO 4

20 Classification of Textile Flame Retardants Non-Durable Flame Retardants (Top Treatments) Need for more sophisticated flame retardants for higher processing speeds and more demanding applications Phosphonates generally have higher thermal stability than APP s allowing higher processing speeds Flame Retardants capable of being processed at temperatures of over 130ºC have been developed by Rhodia and marketed under the AMGARD trademark Some of the AMGARD products are based on phosphonate chemistry which generally have higher thermal stability than APP s

21 Classification of Textile Flame Retardants Semi-Durable Flame Retardants Used for items not normally washed but may be subjected to water soak or dry cleaning Ammonium polyphosphates may be used End uses include upholstery and curtains

22 Summary Introduction How Do Textiles Burn? The Action of a Phosphorus Flame Retardant Flame Retardant Selection Classification of Textile Flame Retardants Inherent Flame Retardant Fibres Methods of Application Flammability Standards and Testing HSE Considerations Conclusions

23 Inherent Flame Retardant Fibres Phosphorus containing FR additive can be incorporated into the spinning dope during manufacture of viscose fibres Polyester fibres can also be given FR properties by inclusion of phosphonic acid based derivative

24 Inherent Flame Retardant Fibres CH 3 C O S P O S P O CH 3 C CH 3 O O CH 3 Viscose spinning bath additive for flame retardant rayon O OCH 2 OCH 2 O Cl P C P Cl OCH 2 OCH 2 Spirocyclic pentaerythritol di(phosphate acid monochloride additive for polyester

25 Summary Introduction How Do Textiles Burn? The Action of a Phosphorus Flame Retardant Flame Retardant Selection Classification of Textile Flame Retardants Inherent Flame Retardant Fibres Methods of Application Flammability Standards and Testing HSE Considerations Conclusions

26 Methods of Application Mangle Rollers Drying Area Pad Mangle Fabric roll Stenter Fabric roll

27 Methods of Application Padding (full impregn ation) Mangle rollers Fabric Lick Roll Fabric Pad trough Low viscosity paste Screen coating (backcoating) Foam or paste Mesh -screen Knife or squeegee Fabric Steel support roller

28 Methods of Application Knife over air Paste Knife Fabric (Back-coating) Steel roller Steel roller Knife over roll Knife (Back-coating) Fabric Paste Steel roller

29 Methods of Application Pad Mangles

30 Methods of Application Stenter Drying

31 Methods of Application Textile Coating Machines

32 Methods of Application Wet Processing (Dyeing) machines Jig Dyeing machine Winch Dyeing Machine Jet Dyeing Machine

33 Methods of Application Wet Processing (Dyeing) machines Continuous Wash Ranges

34 Summary Introduction How Do Textiles Burn? The Action of a Phosphorus Flame Retardant Flame Retardant Selection Classification of Textile Flame Retardants Inherent Flame Retardant Fibres Methods of Application Flammability Standards and Testing HSE Considerations Conclusions

35 Flammability Standards and Testing Standards and testing are vital in ensuring that the flammability performance of a fabric is satisfactory for a specific end-use Flammability testing must be carried out in accredited test laboratories using recognised flammability test methods There are a range of national and international flammability standards

36 Flammability Standards and Testing Protective Clothing (woven & or knitted) for use in the European Community EN 533: 1997 Index 3, EN 531: 1995 para EN 470: Part 1: 1995 para 6.1 after 50 washes at 75 C (according to EN Standard wash). UK Sheeting & Blankets BS7175 Ignition sources 0, 1 & or 5 when tested on top of & or below the test fabric, after 200 washes at 74 C. UK Curtaining BS 5867 Part 2 Type B after 50 washes at 74 C. Mattress Ticking BS 7175 Ignition sources 0, 1& or 5 when tested on top of & or below the test fabric, after 3 washes at 74 C. UK Upholstery BS 5852 Part 1 Ignition sources 0 & 1 after a water soak treatment BS 5651.

37 Flammability Standards and Testing EN 532 standard for work wear

38 Flammability Standards and Testing BS 7175 on Continental quilts Crib 5 test

39 Flammability Standards and Testing EN 348 standard for work wear

40 Flammability Standards and Testing DOC FF3-71 standard for children s sleepwear

41 Summary Introduction How Do Textiles Burn? The Action of a Phosphorus Flame Retardant Flame Retardant Selection Classification of Textile Flame Retardants Inherent Flame Retardant Fibres Methods of Application Flammability Standards and Testing HSE Considerations Conclusions

42 HSE Considerations In recent years all chemicals are coming under increased scrutiny, especially halogen containing flame retardants Further pressure from REACH proposals (the Registration, Evaluation and Authorisation of Chemicals) in the EU due to become operational in spring 2007 High customer expectation in terms of safety of chemical finishes Ecolabels such as Öko-Tex (or Blue Angel) whereby the endorsement confers safe toxicological and environmental profiles of the relevant chemicals

43 Conclusions Ever increasing pressure on chemical manufacturers to produce finishes which have a good tox and environment profile, and are cost and performance effective General move away from halogen containing flame retardants Challenge for the future will be to develop more efficient flame retardant finishes in terms of application and also performance Also multi-function finishes for textiles where flame retardant performance is imparted along with other properties, e.g. antimicrobial, soil/stain resist Reference: R Padda and G Lenotte, General Trends in Textile Flame Retardants, Speciality Chemicals Magazine, 2005,

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