This is about flame retardant finishes used widely in textile sector.

1. 1
Flame Retardants
Engr. Nasir Sarwar

2. INTRODUCTION
2
 Flame-retardant finishes provide textiles with an important
performance characteristic that is it stopped the propagation of
fiber when it comes in contact with fire.
 NEEDS OF FLAME RETARDANTS
 Protection of consumers from unsafe apparel
 Firefighters and emergency personnel require protection
 Floor coverings, upholstery and drapery protection
 The military
 the airline industry

3. 3
Organic material and fire
Fire breaks: 12 million per years (Europe, USA, Russia, China)
Deaths: 0.3 millions per years
Property loss:$500 million per years (Grover et. al., 2014).
Importance of eco fire retardant due to the strict health and safety rules and
more awareness among customers (Jiang et al.2015).
USA and EU federal flammability standard (Wu and yang, 2007).
Uses of fire retardant in various areas
Clothing (fire fighter apparel, industrial worker clothing, military garments,
baby garment, cotton flees)
Carpet, transportation, professional racers
Institutional and domestic upholstery (curtain, sofa seat, bed sheet).
Electric wire insulation, wooden products and foam mattress (Well 2008).

4. Types of F.R. Fabric In Industry
4
Fabric which has to be padded with F.R.
chemical
Fabric which is made flame retardant at the
time of manufacturing of yarn

5. HISTORY
5
About 450 BC EGYPTIANS used ALUM to reduce
flammability of wood
In 1638 clay & gypsum used for theater curtains.
1821 GAY-LUSSAC mixture of borax & ammonium salt of
phosphoric acid for linen
1913 Perkin gives FR treatment for cotton by using so.
Stannite & ammo. Sulphate.

6. Mechanisms of flame retardancy
6
 Combustion:
is an exothermic process
that requires three
components,
Heat
oxygen
suitable fuel.

7. Mechanisms of flame retardancy
7
 Pyrolysis temperature, TP,
 At this temperature, the fiber
undergoes irreversible chemical
changes, producing
 non-flammable gases (carbon
dioxide, water vapor and the higher
oxides of nitrogen and sulfur),
 carbonaceous char,
 tars (liquid condensates) and
 flammable gases (carbon
monoxide, hydrogen and many ox
disable organic molecules).

8. Mechanisms of flame retardancy
8
 the combustion temperature, TC,
 At this point, the flammable gases combine with
oxygen in the process called combustion,
 which is a series of gas phase free radical reactions.
 These reactions are highly exothermic
 and produce large amounts of heat and light.

9. Some combustion Cycle Disruption Techniques
9
1. Heat Sink on / in the fiber
2. Insulating Layer
3. Condensed Phase: reaction to produce less
flammable volatiles and more residual char.

10. Combustion Cycle Disruption Techniques
10
1. Heat Sink on / in the fiber
by use of materials that thermally decompose through
strongly endothermic reactions.
 If enough heat can be absorbed by these reactions, the
pyrolysis temperature of the fiber is not reached and
no combustion takes place.
Examples of this method are
the use of aluminum hydroxide or ‘alumina rehydrate’
and calcium carbonate as fillers in polymers and
coatings

11. Combustion Cycle Disruption Techniques
11
2. Insulating Layer
 to apply a material that forms an insulating layer around the
fiber at temperatures below the fiber pyrolysis temperature.
Boric acid and its hydrated salts function in this capacity. When
heated, these low melting compounds
 release water vapor
 and produce a foamed glassy surface on the fiber,
insulating the fiber from the applied heat and oxygen.

12. Combustion Cycle Disruption Techniques
12
 Condensed Phase: reaction to produce less
flammable volatiles and more residual char.
This ‘condensed phase' mechanism can be seen in the
action of phosphorous-containing flame retardants
which, after having produced phosphoric acid
through thermal decomposition,
crosslink with hydroxyl-containing polymers thereby
altering the pyrolysis to yield less flammable by-
product.

13. Combustion Cycle Disruption Techniques
13
 The ‘condensed phase’ strategy includes
the described mechanism
of removal of heat and the enhancement
of the decomposition temperature as in
heat resistant fibers.

14. thermal degradation mechanism of cellulose fibres (cotton,
rayon,linen, etc.) is the formation of the small depolymerisation
product levoglucosan.
14

15. Flame retardants for cellulose
 Levoglucosan:
 Levoglucosan and its volatile pyrolysis products are
extremely flammable materials and are the main
contributors to cellulose combustion.
 Compounds that are able to hinder levoglucosan formation
are expected to function as flame retardants for cellulose.
15

16. Flame retardants for cellulose
 Levoglucosan:
 The crosslinking and the single type of esterification of cellulose polymer chains by
phosphoric acid reduces levoglucosan generation, catalyses dehydration and
carbonisation, and thus functions as an effective flame retardant mechanism.
 This carbonisation of cellulose is similar to the well knowncarbonisation process of wool
with sulfuric acid, removing plant dirt and other cellulosics.
 In an idealised equation, flame-retardant finished cellulose (C6H10O5)n would be
decomposed to 6n C and 5n H2O. The first step of this reaction is shown in Fig. 8.6.
 The resulting char is much less flammable than the volatile organic pyrolysis products of
untreated cellulose.
Esterification is a process involving the interaction of a compound possessing a hydroxyl group (oH)with an
acid, with the elimination of water.
16

17. Flame retardants for cellulose
 Chemicals that can yield phosphoric acid during the
early stages of fibre pyrolysis
 form the majority of successful flame retardants for cellulose.
 The presence of nitrogen has been found to provide
 a synergistic effect with phosphorous.
 Minimum levels of added phosphorous and nitrogen
for effective flame retardancy have been estimated
 at ~ 2% P and ~1 % N. depending on fabric construction and test
requirements.
17

18. Comparison of two permanent
flame-retardant finishes for
cellulosics
Modified THPC–urea
finish(‘Proban’ type)
 Demanding process, including
 moisture control,
 ammonia vapour treatment
 and oxidation
 Smaller wash shrinkage
 Better stability to hydrolysis
 Somewhat better ripping strength
 Less odour bothering
 Also for fibre blends with small
cellulose content
 Preferably for large production
runs,
 to minimise the process costs
including machinery requirements
N-methylol phosponopropionamide
finish(‘Pyrocatex CP new’ type)
 Extra washing after curing
including
 drying costs
 Softer handle
 Fewer dyestuff restrictions,
including brilliant shades After
handle
 Much less free formaldehyde
development
 Shorter after-burning time
 Less smoke development
 No licence required, including
 corresponding restrictions and
costs
18

19. 19
 The history of fire retardant chemicals.
 It goes back to 100 B.C.
 Proper documentation (Pat.515 (1735).
 Gay–Lussac ……Fire retardancy due to aluminum salt (Lussac 1821).
 Serious work regarding durable phosphorous based fire retardant
cotton garments (Well, 2008).
 Most widely used fire retardant
 N-methyloldimethylphosphonopropionamide (MDPA), which is
commercially known as Pyrovatex CP (Mohsin et al. 2013). Formaldehyde
and carcinogenic issues
 Enhancer
 Trimethylol melamine (TMM) is typically recommended.
Formaldehyde and carcinogenic issues
Fire retardants and chemistry
(1. MDPA)

20. 20
 The optimized Pyrovatex recipe has environmental and health
issues.
 eye and skin irritation, headaches, difficulty in breathing (
Ravichandran et al. 2011).
 Formaldehyde is confirmed human carcinogenic (cancer causing
substance) by World Health Organization and International Agency for
Research on Cancer (Mohsin et al. 2013).
 Strict formaldehyde level limits have been imposed in all countries
and even it is already completely banned in few countries. In case of
child clothing formaldehyde is not allowed all over the world.
 The hydroxyl functional organophosphorus oligomer commercial
known as Fyroltex HP and functional group & cross-linkers.
(Yang et al. 2005).
Continue…

21. 21
 Second most commonly used fire retardant
 Tetrakis hydroxymethylphosphonium chloride (THPC).
 Ammonia Chamber (Wu and yang 2005; Pan et al. 2014).
 Cross-linker & Tetra Carboxylic acid
(Mohsin et al.2013; Yang et al. 2003; Karim-nejad et al. 2014).
 Additives
 Silicon
Nitrogen (Chen 1996).
The flammability of cotton can be suppressed by using combination of
phosphorus/silicon containing fire retardants (Zaho, 2010).
Fire retardants and chemistry
(2. THPC)

22. 22
 The boron is a fire retarding element.
 Borates and boric acid (Hendersinn,1977).
 The fire retardant that contain boron are cheaper and less toxic as
compare to antimony oxide (Arthuretet. al.1992).
 The aromatic boric acid is used in polymeric material as compare
to simple boric acid. However, these boron containing fire retardants
are non durable. The boric acid can be used as enhancer with Pyrovtex
Cp new (Dechirico et al. 1993).
 The nitrogen is also not inherently fire retardant but it gives
excellent synergetic effect with phosphorous for example TMM (Lu and
Hamerton, 2002).
Fire retardants and chemistry
(3. Boron based)

23. 23
 It is well known that Halogen containing fire retardants are
dangerous
to human body. The halogens are consider as
 Global containments and are associated with adverse health effects
in humans and animals,
 Including endocrine and thyroid disruption,
 Immunotoxicity, reproductive toxicity,
 Cancer and adverse effects on fetal and child development and
neurological function(Shaw et al. 2010).
 Metal salts; It is explored that salts of Magnesium (Mg), Chromium
(Cr),
Manganese (Mn), Tin (Sn) and Barium (Ba) are also impart fire
retardant to some extent (Wdwards et al. 2014).
(4. Halogen based & metal salts)

24. Issues with currently available fire retardant
The fire retardants that are currently available have following problems;
 Release of carcinogenic formaldehyde
 Less performance efficient
 Poor washing durable
 Expensive
 Difficult application
 Non environment friendly
 Contain toxic halogens
The solution of above problem is synthesis of novel, performance
effective, environment friendly, halogen free and zero formaldehyde
phosphorous based fire retardants, with zero formaldehyde based
carboxylic acid based eco cross-linkers.
24

25. Testing of flame retardants
The visual timing test- vertically
The 45 degree test – 5 inch distance at such
angle
Hoop test- semi circular frame
25

26. LOI
 LIMITED OXYGEN INDEX is give us some
information about flame retardancy
 It is the minimum % of oxygen in oxy- nitro
atmosphere require to sustain combustion
L.O.I. = (O2)/(O2+N2)* 100
HIGHER THE LOI MEANS MORE THE FLAME
RETARDENT
26

27. Factor affecting the f. resistance
Fiber content
Fabric structure
weight
27

28. Problems with flame retardant
Toxicity
Irritated towards skin
Durability
Flexibility
28

29. 29

30. 30

31. Protective clothing for fire
fighter (APPLICATION)
NATIONAL FIRE PROTECTION ASSOSIATION has set
a fundamental requirement that it’s TPP value must
be 35 minimum.
According to NFPA each far. cloth ,, contain three
component –
Outer shell
Moisture barrier
Thermal barrier
31

32. Protective clothing for fire
fighter
 As an example LOS ANGELOUS fire department
used-
 outer shell –nomex/kevlar in a rip stop weave
Thermal insulator
Moisture barrier
32

33. 33
Organic material and fire
Fire breaks: 12 million per years (Europe, USA, Russia, China)
Deaths: 0.3 millions per years
Property loss:$500 million per years (Grover et. al., 2014).
Importance of eco fire retardant due to the strict health and safety rules and more
awareness among customers (Jiang et al.2015).
USA and EU federal flammability standard (Wu and yang, 2007).
Uses of fire retardant in various areas
Clothing (fire fighter apparel, industrial worker clothing, military garments, baby
garment, cotton flees)
Carpet, transportation, professional racers
Institutional and domestic upholstery (curtain, sofa seat, bed sheet).
Electric wire insulation, wooden products and foam mattress (Well 2008).

34. Issues with currently available FR
The fire retardants that are currently available have following problems;
 Release of carcinogenic formaldehyde
 Less performance efficient
 Poor washing durable
 Expensive
 Difficult application
 Non environment friendly
 Contain toxic halogens
The solution of above problem is synthesis of novel, performance effective,
environment friendly, halogen free and zero formaldehyde phosphorous based fire
retardants, with zero formaldehyde based carboxylic acid based eco cross-linkers.
34

35. Fire retardants and chemistry
(1. MDPA)
 The history of fire retardant chemicals.
 It goes back to 100 B.C.
 Proper documentation (Pat.515 (1735).
 Gay–Lussac ……Fire retardancy due to aluminum salt (Lussac 1821).
 Serious work regarding durable phosphorous based fire retardant cotton garments (Well,
2008).
 Most widely used fire retardant
 N-methyloldimethylphosphonopropionamide (MDPA), which is commercially known
as Pyrovatex CP (Mohsin et al. 2013). Formaldehyde and carcinogenic issues
 Enhancer
 Trimethylol melamine (TMM) is typically recommended. Formaldehyde and carcinogenic
issues
35

36.  The optimized Pyrovatex recipe has environmental and health issues.
 eye and skin irritation, headaches, difficulty in breathing (
Ravichandran et al. 2011).
 Formaldehyde is confirmed human carcinogenic (cancer causing
substance) by World Health Organization and International Agency
for Research on Cancer (Mohsin et al. 2013).
 Strict formaldehyde level limits have been imposed in all countries
and even it is already completely banned in few countries. In case of
child clothing formaldehyde is not allowed all over the world.
 The hydroxyl functional organophosphorus oligomer commercial
 known as Fyroltex HP and functional group & cross-linkers.
 (Yang et al. 2005).
36

37. THPC
 Second most commonly used fire retardant
 Tetrakis hydroxymethylphosphonium chloride (THPC).
 Ammonia Chamber (Wu and yang 2005; Pan et al. 2014).
 Cross-linker & Tetra Carboxylic acid
 (Mohsin et al.2013; Yang et al. 2003; Karim-nejad et al. 2014).
 Additives
 Silicon
 Nitrogen (Chen 1996).
 The flammability of cotton can be suppressed by using combination of
phosphorus/silicon containing fire retardants (Zaho, 2010).
37

38. Boron Based FR
 The boron is a fire retarding element.
 Borates and boric acid (Hendersinn,1977).
 The fire retardant that contain boron are cheaper and less toxic as
compare to antimony oxide (Arthuretet. al.1992).
 The aromatic boric acid is used in polymeric material as compare to
simple boric acid. However, these boron containing fire retardants are
non durable. The boric acid can be used as enhancer with Pyrovtex Cp
new (Dechirico et al. 1993).
 The nitrogen is also not inherently fire retardant but it gives
excellent synergetic effect with phosphorous for example TMM (Lu and
Hamerton, 2002).
38

39. Halogen Based FR
 It is well known that Halogen containing fire retardants are dangerous
 to human body. The halogens are consider as
 Global containments and are associated with adverse health effects
 in humans and animals,
 Including endocrine and thyroid disruption,
 Immunotoxicity, reproductive toxicity,
 Cancer and adverse effects on fetal and child development and
 neurological function(Shaw et al. 2010).

 Metal salts; It is explored that salts of Magnesium (Mg), Chromium (Cr),
 Manganese (Mn), Tin (Sn) and Barium (Ba) are also impart fire
 retardant to some extent (Wdwards et al. 2014).Helogen Based FR
39

40. .
NON textile Application
The fire retardancy of insulation of electrical wires in electronic
and electrical industry has been improved by using
 suitable fire retardant (Qian et al. 2014; Menardet et. al.2014).
The ethylene propylenediene monomer and its uses
 Like weather stripping and seals, radiator, garden and appliance
hose, tubing, belts, electrical insulation and roofing membrane.
 The drawback of this material is only that it catches fire easily. It
can be overcome by adding flame retardant (Wen et al.2014)
40

41. Consideration:
 Chemical
finishing of textiles W. D. Schindler and P. J.
Hauser.

41