Introduction: With industrialization, the safety of human beings has become an important issue A growing segment of the industrial textiles industry has therefore been involved in a number of new developments inﬁbres,fabrics,protective clothing. Major challenges to coatings and fabrication technology for production in the ﬂame- retardant textile industry have been to produce environmentally friendly, non- toxic ﬂame-retardant systems that complement the comfort properties of textiles
What is a Flame Retardant?Flame retardants are materials that have the quality ofinhibiting or resisting the spread of fire.Textile is highly ignitable and contributes to rapid fire spread.However, the ignitable property of a textile can beconsiderably reduced by any one of the three methods-using inorganic materials such as Asbestos, Glass etc.;chemically treating the textile with Flame Retardantchemicals; andmodifying the polymer
Functions of a Flame Retardant:chemicals are applied to fabrics to inhibit or suppress thecombustion process.They interfere with combustion at various stages of theprocess e.g. during heating, decomposition, ignition offlame spread.Fire is gas phase reaction. For a substance to burn, it mustbecome a gas. As with any solid, a textile fabric exposed to aheat source experiences a temperature rise.If the temperature of the source is((either radioactive orgas flame)) high enough and the net rate of heat transfer tothe fabric is great
Functions of a Flame Retardant: The products of this decomposition include combustible gases, non-combustible gases and carbonaceous char. The combustible gases mix with the ambient air and its oxygen. The mixture ignites, yielding a flame, when its composition and temperature are favorable. Part of the heat generated within the flame is transferred to the fabric to sustain the burning process and part is lost to the surroundings.
Categories of Flame Retardants : Tetrakis (hydroxymethyl) phosphonium salts that are made by passing phosphine gas through a solution of formaldehyde and a mineral acid like hydrochloric acid. This category is mostly used as flame retardants for textiles. Minerals like asbestos, compounds such as aluminum hydroxide, magnesium hydroxide, antimony trioxide different hydrates, red phosphorus, and boron compounds, mostly borates. Etc.
Synthetic materials, usually halocarbons which include organochlorines such as polychlorinated biphenyls (PCBs), chlorendic acid derivates and chlorinated paraffins; organobromines such as polybrominated diphenyl ether (PBDEs), organophosphates in the form of halogenated phosphorus compounds and others.if we talk of the types of flame retardants,they are:Brominated flame retardantsChlorinated flame retardantsPhosphorous-containing flame retardants (Phosphate ester such as Tri phenyl phosphate)Nitrogen-containing flame retardants (i.e. Melamines)
Inorganic flame retardants.Other method of classifying Flame Retardants is todivide them as Inorganic,1)Organo Phosphorous,2)Halogenated organic and3)Nitrogen based compounds.Halogenated organic flame retardants are furtherclassified as having either Chlorine or Bromine which ispopularly known as Brominated Flame Retardants(BFR)
Mechanisms of Flame Retardants Mechanisms of Flame Retardants:Flame retardants can act physically orchemically and sometimes both by physicallyand chemically interfering at particular stagesof burning
Endothermic Degradation: Certaincompounds break down endothermically when theyare subjected to high temperatures. Magnesium andaluminum hydroxides are such examples. Varioushydrates also act similarly. The reaction takes offheat from the surroundings, thus cooling the material
Dilution of Fuel:Substances, which evolve inert gases ondecomposition, dilute the fuel in the solid and gaseousphases. Inert fillers, eg.talc or calcium carbonate, act as diluents, lowering thecombustible portion of the material, thus lowering theamount of heat per volume of material that it canproduce while burning. Thus the concentrations ofcombustible gases fall under the ignition limit
Thermal ShieldingA thermal insulation barrier is created between theburning and the yet-to-burn parts. Intumescentadditives are sometimes applied that turn the polymerinto a carbonized foam, resultantly separating the flamefrom the material and slowing down the heat transfer tothe unburned fuel
Dilution of Gas Phase : Inert gases, mostly carbondioxide and water, act as diluent of the combustible gases,lowering their partial pressure of oxygen, thus slowing thereaction rate. These gases are produced by thermaldegradation of some materials.
Application of Flame Retardants onTextiles: Flame Retardants on fabric can be applied through conventional padding, padding with multiple dips and nips If followed by 30 to 60 seconds well, it gives good results. The pH of the pad bath is optimally kept at approximately 5.0. The amount of flame retardant required depends primarily on the fabric type, application conditions, and test criteria required to be met with. Screening experiments should be conducted to determine the minimum application level for a fabric
Use of Flame Retardant in Textiles Upholstered furniture is made of three parts (cover fabrics,upholstery and interliner) and some of these products smoulder andlead to the start of a fire.Synthetic fibers may burn fiercely and any already burningresidue, may drip, carrying flames to other surfaces.Foams, which are not treated by fire retardants, ignite easily andwill burn if the material is in contact with a flame.Flame retardants are also be incorporated into the cover fabrics,upholstery or/and interliner, and in this case linked to the matrix,forming a new chemical product.
Conclusion: Most ﬂame-retardant textiles are designed to reduce the ease of ignition and also reduce the ﬂame propagation rates. The increasing need to use environmentally friendly FR ﬁnishes has been emphasized