Cellulose flame-retardant finishes

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. 

Additives. Because of their versatility, imparted via chemical modification, the applications of ethyleneimine encompass the entire additive sector. The addition of PEI to PVC plastisols increases the adhesion of the coatings by selective adsorption at the substrate surface (410). PEI derivatives are also used as adhesion promoters in paper coating (411). The adducts formed from fatty alcohol epoxides and PEI are used as dispersants and emulsifiers (412). They are able to control the viscosity of dispersions, and thus facilitate transport in pipe systems (413). Fatty acid derivatives of PEI are even able to control the viscosity of pigment dispersions (414). The bigb nitrogen content of PEIs has a flame-retardant effect. This property is used, in combination with phosphoms compounds, for providing wood panels (415), cellulose (416), or polymer blends (417,418) with a flame-retardant finish. 

Abdel-Mohdy, F. A., Graft copolymerization of nitrogen- and phosphorus-containing monomers onto cellulosics for flame-retardant finishing of cotton textiles, J. Appl. Polym. Sci., 2003, 89, 2573-2578. 

Table 8.3 Comparison of two permanent flame-retardant finishes for cellulosics...

A permanent flame retardant finish for cellulose fibers. PROTE-NYL BN-5724-S ... 

Since cellulosic fibres are sensitive to acids they can be easily damaged by the acid catalysts used in easy-care, silicone, fluorocarbon and flame-retardant finishes as well as by drops of concentrated acid or faulty dyeing of cellulose/wool blends. 

Melamine—Forrnald6hyd6 Resins. The most versatile textile-finishing resins are the melamine-formaldehyde resins. They provide wash-and-wear properties to cellulosic fabrics, and enhance the wash durability of flame-retardant finishes. Butylated melamine-formaldehyde resins of the type used in surface coatings may be used in textile printing-ink formulations. A typical textile melamine resin is the dimethyl ether of trimethylolmelamine [1852-22-8], which can be prepared as follows ... 

Ammonium Sulfamate [7773-06-0]. This salt is similar to ammonium sulfate but somewhat less acidic and corrosive. It is applied as an aqueous solution to paper or cellulosic fabric to obtain a flame retardant finish nondurable to washing. It has fairly good afterglow retardation. 

Flame-Retardant Finishes on Cellulosic Substrates. The flame retarding of cotton and viscose-rayon fabrics has been the object of a large worldwide effort on phosphorus-containing finishes (217-219). The commercial cotton finishes are based on tetrakis(hydroxymethyl)phosphonium salts, usually the chloride or sulfate (220). These salts are prepared by reaction of formaldehyde with phosphine in the presence of an acid. 

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 Finishes Cellulosic fibers are among the more flammable fibers and are subject to rapid flaming combustion as well as slow... 

Ammonia—Gas-Cured Flame Retardants. The first flame-retardant process based on curing with ammonia gas, ie, THPC—amide—NH, consisted of padding cotton with a solution containing THPC, TMM, and urea. The fabric was dried and then cured with either gaseous ammonia or ammonium hydroxide (96). There was Httle or no reaction with cellulose. A very stable polymer was deposited in situ in the cellulose matrix. Because the fire-retardant finish did not actually react with the cellulose matrix, there was generally Httle loss in fabric strength. However, the finish was very effective and quite durable to laundering. 

Early Durable Finishes. Early studies lo produce durable flame retardants for cellulose were based on treatment wilh inorganic compounds containing antimony and titanium. 

In commercial use, easy-care and durable press finishes are frequently combined with other finishes to provide additional properties such as water and oil repellency, flame retardancy, soil release and the like. Often the combination of another finish with the cellulose crosslinking finish will result in a more durable effect from the first finish. Combination with pigment printing is very common because of similar chemistry to cellulose crosslinking agents and binders and the similar application conditions. 

Although inorganic salts can provide excellent flame-retardant properties for cellulose, reasonable laundering durability must be incorporated into any finish destined for apparel use. The most successful durable flame retardants for cellulose are based on phosphorous- and nitrogen-containing chemical systems that can react with the fibre or form crosslinked structures on the fibre. The key ingredient of one of these finishes is tetrakis(hydroxymethyl)phosphonium chloride (THPC), made from phosphine, formaldehyde and hydrochloric acid (Fig. 8.11). THPC reacts with urea to form an insoluble structure on cellulose in a pad-dry-cure process (Fig. 8.12). 

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... 

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]. 

Uses Flame retardant, plasticizer for PVC and copolymers, PVAc, acrylics, finished film or coated fabric applies., vinyl plastisols, PVC adhesives, ethyl cellulose, NC, SBR and butyl rubbers plasticizer for flooring, cast and calendered free film and sheeting, extrusion, slush molding, inks, coatings, adhesives, sealants, elastomers, plastisols, wire and cable... 

Chem. Descrip. Tributoxyethylphosphate CAS 78-51-3 EINECS/ELINCS 201-122-9 Uses Emulsifier, wetting agent, plasticizer, dispersant, leveling agent for acrylic floor finishes lowers vise, of PVC plastisols plasticizer for acrylonitrile and other rubbers flame retardant for acrylic, cellulosics, nitrile, PS... 

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. 

Vinyl fibers except for vinal and vinal-vinyon do not generally undergo specialized finishing, although antioxidants and antistatic agents may be used. Vinal and vinal-vinyon matrix fibers can be treated with urea-aldehyde based durable press finishes to improve their wrinkle recovery, and vinal can be made flame retardant with phosphorus-containing finishes used for cellulosics. 

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