Cellulose flame resist finish

Nearly all successful flame-resistant finishes depend upon the application of compounds contuining phosphorus to the cellulose. Not much is known about the combustion of cellulose, but it has been established that it breaks down into a solid carbonaceous char accompanied by the formation of volatile liquids, gases, and tarry substances. Anything which reduces the formation of volatile products of combustion will retard the rate of propagation... 

Several commercial flame-resistant finishes are based on esterification of the cellulose with phosphoric acid (Perfect, y.S.D.C., 1958, 74, 829) ... 

Fire Retardants for Ceftnlosics. Phosphorus-containing materials are by far the most important class of compounds used to imparl durable flame resistance lo cellulose. Flume-retardant finishes containing phosphorus compounds usually also contain nitrogen or bromine or sometimes huth. 

Viscose In principle all the treatments effective on cotton should be effective on viscose as well. However, the delicate viscose libers cannot withstand the harsh finishing processes, and are rarely treated with a finish. However, Lyocell (Coutaulds) can be treated with Pyrovatex CP (Ciba) to produce FR Lyocell.55 The work at Bolton has shown that this fiber being more reactive than cotton needed only half the normal amount of this FR treatment applied to cotton cellulose to produce an equivalent degree of flame resistance. 

It is in rtant to keep in mind that considerable amounts of these compounds (about 20% of the fiber wei ) are required in order to develop an appreciable flame resistance and that a final thermal treatment u necessary to make the coating sufficiently wa i of. The use of these compounds results in tenadty loss of 25%-30%. Another difficulty arises when treating blends of standard PET fibers and cellulosics with finishing baths containing such compounds, which general hai% a h%her affinity for cellulosics than for polyesters. This trouble may be partially, overcome by uang finishing baths of a suitable composition... 

Cellulosics have certain deficiencies in properties that require finishing to improve these properties and maximize consumer usage and acceptance. The most important cellulosic finishes include crease resistant and stabilizing finishes, soil release and softening finishes (in conjunction with crease resistant finishes), oil and water repellant finishes, biologically protective finishes, and flame retardant finishes. 

Flame-retardant textiles are textiles or textile-based materials that inhibit or resist the spread of fire. Factors affecting flammability and thermal behavior of textile include fiber type, fabric construction, thermal behavior of textile polymer and its composition as well as the presence or absence of flame additives. On the other hand, flame-retardant additives can be classified by their chemical composition or by mode of action, i.e., gas phase action or by the formation of protective barrier [49, 50]. Moreover, flame-retardant functional finishes of cellulose-based textiles can be accomplished by [i] using inorganic phosphates, (ii) with organophosphorous compounds, [iii) with sulfur-derivatives or (iv) by grafting flame retardants monomers [49,50]. 

Ammonium Phosphates. Monoammonium Phosphate [7722-76-1], NH4H2PO4, and diammonium phosphate [7783-28-0], (NH4)2HP04 (or mixtures of the two), have long been used for low cost flame retarding and afterglow prevention of paper, textiles, disposable nonwoven cellulosic fabrics, and wood products (42-44). Ammonium phosphate finishes are resistant to dry-cleaning solvents but not to water. 

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