Flame retarding performance

Combination Flame Retardant—Durable Press Performance. Systems using THPC, urea, and TMM can be formulated to give fabrics which combine both flame-retardant performance and increased wrinkle recovery values (80). Another system employs dimethylol cyanoguanidine with THPC under acidic conditions (115). Both of these systems lead to substantial losses in fabric tensile and tearing strength. 

Another fire-related problem that has seen some research effort is that of smolder resistance of upholstery and bedding fabrics. Finishing techniques have been developed to make cotton smolder-resistant (152—156), but the use of synthetic barrier fabrics appears to provide a degree of protection. Work also has provided a means of producing cotton fabrics that have both smooth-dry and flame-retardant performance (150,151). In this case, the appHcation of FR treatment should be performed first, and DP treatment should be modified to accommodate the presence of the FR polymer on the fabric. 

Major disadvantages of inorganic FRs are their relatively low decomposition temperature and requirement of a large fraction of material to give sufficient flame retardant performance in most polymers. 

A significant advantage to performing well with a wide range of flame retardants is formulating flexibility. There are many factors which limit the choice of flame retardants asided from flame retardant performance and compatability. For example, environmental constraints (no antimony to the sewer, no ammonia in the workplace) and compatability constraints (shorter than normal shelf life with certain emulsions) may limit the choice. 

The flame retardant performance of the three flame retardants in a commercial polycarbonate/PET polyester alloy were compared. 

The flame retardant performance of various flame retardant additives in a commercial polycarbonate/ABS alloy were compared. No antimony oxide was required. The data shows brominated phosphate to be a highly efficient flame retardant in this alloy (Table XI). An alloy composition containing 14% brominated phosphate and no antimony oxide gives a V-0 rating (Table XII). The melt index of this alloy containing 12% brominated polystyrene was 7.6 g/10 min. (at 250°C) the equivalent resin containing brominated phosphate had a melt index of 13.3 g/10 min. 

Hong, S., Yang, J., Anh, S., Mun, Y., and Lee, G. Flame retardancy performance of various UL94 classified materials exposed to external ignition sources. Fire Mater. 2004, 28, 25-31. 

Stinson, J.M. and Horn, W.E. Flame retardant performance of a modified aluminum hydroxide with increased thermal stability, Proceedings from Society of Plastics Engineers 52nd Annual Technical Conference (ANTEC 94), Part 3, Newtown, CT, U.S.A, May 1-5, 1994, pp. 2829-2833. 

FIGURE 26.8 Flame propagation height versus time in UL 1685 tray cable burn test. (Whaley, P.D. et al., Nanocomposite flame retardant performance Laboratory testing methodology, in Proceedings of the 53rd IWCS/Focus International Wire Cable Symposium, 2004, pp. 605-611.)... 

FYARESTOR 102 is a bromochlorinated paraffin that performs as an effective flame retardant plasticizer in coated fabrics formulations for synthetic and natural fiber blends. Similar to chlorinated paraffins, FYARESTOR 102 offers greater flame retardant performance due to its functional bromine levels, yet retains similar plasticizer performance due to its low viscosity. 

The third most commonly used class of flame-retardants is phosphorus-containing compounds such as phosphoric acid esters, diphenyl cre-sylphosphate, dimethyl methylphosphonate, and dibutyl dihydroxyethyl diphosphate. They have good flame-retarding performance and are effective in small amounts. They are, however, expensive and have low hydrolysis stability. 

These additives were tested as flame retardants is rigid urethane foams. The results of one set of these tests are shown in Table 4, where the flame retarding performance of these additives... 

In contrast to bromine, phosphorus based polymers are an effective class of flame retardant materials (85). In particular, they exhibit a good flame retardant performance and are thus preferred in com-... 

Flame retardant performance can be enhanced in some magnesium hydroxide protected systems by the incorporation of clay or talc. In a polyethylene formulation the addition of 60% magnesium hydroxide and 5% tale instead of 65% magnesium hydroxide, improved the V-0 rating from 3.2 mm to the thinner 1.6 mm level. More tale at the expense of further magnesium hydroxide dropped the V-0 rating baek to 3.2 mm. 

Phosphoms may be incorporated into PMMA to reduce flammability. Work carried out at Salford University has shown that MMA may be reacted with diethyl(methacryloxymethyl) phosphonate (DEMMP) to form a copolymer that provides a better flame retardant performance than a compound to which diethyl ethyl phosphonate (DEEP) has been added. DEEP has a similar stmcture to DEMMP and it might be expected that the two compounds confer a similar degree of flame reatardancy to PMMA at similar loadings. The rise in oxygen index is similar, 17.5 up to 22 at 3.5% of phosphoms in each case. However, the MMA/DEMMP copolymer is more thermally stable and gives better FR properties. It turns out that the DEEP plasticises PMMA whereas the copolymer has similar physical and mechanical properties to unprotected PMMA. 

Cosynergists may also be used. Addition of synergetic products such as pentaer-ythritol derivatives, carbohydrates, and spumific agents will significantly improve the flame-retardant performance of APP. Red phosphorus and APP are used in intumescent coatings and paints suitable for materials such as wood and steel as well as polymer systems. 

Super submicron technology is now available to produce antimony synergist with particle sizes below 1 pm. The advantages include applications in flame-retarded fiber without screen-packing problems and reduced UV light absorbency. This will allow next-generation systems to enhance flame-retardant performance and UV durability at the same time. 

Table 6.2 A comparison of the flame retardant performance of aluminium hydroxide (ATH) and MCS [125 phr in crosslinked EVA] ...

Brehme Sven, Schartel Bernhard, Goebbels JUrgen, et al. Phosphorus polyester versus aluminium phosphinate in poly(butylene terephthalate) (PBT) Flame retardancy performance and mechanisms. Polym. Degrad. Stab. 96 no. 5 (2011) 875-884. 

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