Rubber flame retardants

EU, 9,380 tons per year were used for metalworking in 1994. These amounts were reduced significantly in 1998 (2,018 tons per year). Other uses include paints, adhesives and sealants, leather fat liquors, plastics and rubber, flame retardants and textiles and polymeric materials (Table 6). The amounts of SCCPs used in the EU were reduced from 13,208 tons per year to 4,075 tons per year for all uses in 1994 and 1998, respectively. Since 2002, the use of SCCPs in the EU in metalworking and fat liquoring of leathers has been subject to restrictions under EU Directive 2002/45/EC. 

Unichlor. Seville] Chlorinated paraffin used in adhesives, coating, rubber, flame-retardant compds., concrete-curing compds., caulking compds., and cutting oils. 

Chem. Descrip. Tricresyl phosphate CAS 1330-78-5 EINECS/ELINCS 215-548-8 Uses Flame retardant for vinyl compds. processing aid by improving flux rate of compds. containing slow-solvating plasticizers plasticizer for NC lacquers and coatings plasticizer, processing aid for rubbers flame retardant sheeting... 

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... 

In addition to the polymer matrix itself, information may be obtained about additives, such as tackifying resins in rubber, flame retardants in polystyrenes, " plasticizers, antioxidants, etc. The study of polymers using pyrolysis in general has been broadened by techniques permitting hydrolysis and methylation, typically by the addition of tetramethyl ammoifium hydroxide to the sample, as described in a review by Challinor." ... 

D. R. Schult2, Flame Retardants—Specialty Fillers, at the CL Meeting of the 147th Rubber Division, Philadelphia, Pa., May 2—5, 1995, American Chemical Society, Washington, D.C. 

A manufacturer considering using a thermoplastic elastomer would probably first consider one of the thermoplastic polyolefin rubbers or TPOs, since these tend to have the lowest raw polymer price. These are mainly based on blends of polypropylene and an ethylene-propylene rubber (either EPM or EPDM) although some of the polypropylene may be replaeed by polyethylene. A wide range of blends are possible which may also contain some filler, oil and flame retardant in addition to the polymers. The blends are usually subject to dynamic vulcanisation as described in Section 11.9.1. 

Some inorganic fillers are used as flame retardants in rubber base formulations. Flame retardants act in two ways (1) limiting or reducing access of oxygen to the combustion zone (2) reacting with free radicals (especially HO ), thus acting as terminator for combustion-propagation reaction. The additives most widely used as flame retardants for polymers are antimony oxides and alumina trihydrate. 

Other flame retardants and/or smoke suppressants can also be used such as magnesium hydroxide, magnesium carbonate, magnesium-zinc complexes and some tin-zinc compositions. Zinc oxide is a common ingredient in many rubber base formulations used as part of the curing system. At the same time, the action of zinc oxide is similar to that of antimony trioxide, but less effective. 

Antimonious acid H3Sb03 and its salts are less well characterized but a few meta-antimonites and polyantimonites are known, e.g. NaSb02, NaSb305.H20 and Na2Sb407. The oxide itself finds extensive use as a flame retardant in fabrics, paper, paints, plastics, epoxy resins, adhesives and rubbers. The scale of industrial use can be gauged from the US statistics which indicate an annual consumption of Sb203 of some 10000 tonnes in that country. 

Paints are complex formulations of polymeric binders with additives including anti-corrosion pigments, colors, plasticizers, ultraviolet absorbers, flame-retardant chemicals, etc. Almost all binders are organic materials such as resins based on epoxy, polyurethanes, alkyds, esters, chlorinated rubber and acrylics. The common inorganic binder is the silicate used in inorganic zinc silicate primer for steel. Specific formulations are available for application to aluminum and for galvanized steel substrates. 

An electric conductive rubber base containing carbon black is laminated with an electric conductive cover layer of phosphoric acid ester plasticizer and other ionic surfactants to prepare antistatic mats, where the covers have colors other than black. It is also reported that alkyl acid phosphates act as color stabilizer for rubber. Small amounts of phosphate esters are helpful in restoring reclaimed rubber to a workable viscosity [284,290]. Esters of phosphoric acid are used in the production of UV-stable and flame-retarded alkylbenzenesulfonate copolymer compositions containing aliphatic resins and showing a high-impact strength... 

This is another important and widely used polymer. Nanocomposites have been prepared based on this rubber mostly for flame-retardancy behavior. Blends with acrylic functional polymer and maleic anhydride-grafted ethylene vinyl acetate (EVA) have also been used both with nanoclays and carbon nanotubes to prepare nanocomposites [65-69]. 

Chemical pretreatments with amines, silanes, or addition of dispersants improve physical disaggregation of CNTs and help in better dispersion of the same in rubber matrices. Natural rubber (NR), ethylene-propylene-diene-methylene rubber, butyl rubber, EVA, etc. have been used as the rubber matrices so far. The resultant nanocomposites exhibit superiority in mechanical, thermal, flame retardancy, and processibility. George et al. [26] studied the effect of functionalized and unfunctionalized MWNT on various properties of high vinyl acetate (50 wt%) containing EVA-MWNT composites. Figure 4.5 displays the TEM image of functionalized nanombe-reinforced EVA nanocomposite. 

Plastic and rubber additives are both commodity chemicals and specialties. The Handbook of Plastic and Rubber Additives [27] mentions over 13 000 products antioxidants and antiozonants amount to more than 1500 trade name products and chemicals [28], flame retardants to some 1000 chemicals [29] and antimicrobials to over 1200 products [30]. 

Leyden and Rabb [68] have illustrated the rubber formula reconstruction process. Table 2.8 shows some of the difficulties encountered in the reconstruction of a complex wire and cable jacket compound. Forrest [38] has illustrated the reverse engineering of the reasonably complex highly flame retardant elastomer compound of... 

Substances applied to or incorporated in a combustible material (e.g. organic polymers, nylon, vinyl and rubber, etc.) to reduce flammability. Act by retarding ignition, control/douse burning, reduce smoke evolution. Slow down or interrupt the self-sustained combustion cycle when the heat-flux is limited. Flame retardants (FRs) improve the combustion behaviour and alter the combustion process (cool, shield, dilute, react) so that decomposition products will differ from nonflame retarded articles. FRs are usually divided into three classes ... 

Semimetal that occurs as a tin-type, brittle form and as a yellow, unstable, nonmetallic form. Its main use is in alloys to harden other metals. Without the addition of antimony, lead would have remained the "softy" of the Periodic Table. But with antimony, lead ruled the print world and later found use in the production of rechargeable batteries. It can be found in older ceramic glazing (yellow orange). Everyday encounters antimony sulfide in match heads and red rubber, antimony oxide is used as a flame retardant. Pure antimony is starting to become of interest in the electronics sector. 

The performance of aluminium hydroxide/magnesium hydroxide-filled systems can be enhanced by incorporation of zinc hydroxystannate in halogen-free rubbers giving reduced smoke and toxic gas emission, coupled with higher flame retardancy. This action will be complimentary to the water release and endothermic effects of aluminium hydroxide/magnesium hydroxide filler systems. 

Studies at the International Tin Research Institute showed that 2.5% zinc stannate strongly enhanced the flame retardant action of ATH in ethylene-acrylic rubber, and enhanced the char yield (34) (Fig. 5). 

Zinc Borate (2Zn0-3B203-3.5H20) is a unique multifuntional fire retardant. It can function as a flame retardant, smoke suppressant, afterglow suppressant, as well as an anti-tracking agent in polymers. It has been used extnesively as a fire retardant in PVC, polyolefin, nylon, polyester, epoxy, acrylic, urethane, rubbers, etc. 

It is of interest to note that the polymer containing ZnSn(OH) does not burn in air even at 250°C and, accordingly, this composition has a temperature index of at least 50°C above that of the rubber containing ATH alone. The 01 and high temperature 01 data therefore provide substantial evidence as to the benefit of using ZnSn(OH) as a flame-retardant synergist with alumina trihydrate filler. 

Certain inorganic tin compounds are effective flame-retardant synergists when incorporated at a 2.5% level into a 50% ATH-filled ethylene-acrylic rubber composition. Tin-containing elastomer formulations retain their flame-retardant superiority at environmental temperatures up to 250°C, and samples containing 2.5% ZnSn(0H)g do not sustain combustion in air at this temperature. 

Chlorinated additive flame retardants, 11 468-470, 471-473t Chlorinated aromatics, 6 242 decomposition using microwaves, 16 555 Chlorinated butyl rubber, 4 436 development of, 4 434 manufacture, 4 400, 442-444 Chlorinated ethanes... 

Flame-retardant silicone rubber, 22 584 Flame spray coatings, 5 665 Flame temperature, 12 322 Flame temperature, 7 443 Flame throwers, 5 824 Flame working, of vitreous silica, 22 415-416... 

Mirex and chlordecone are no longer made or used in the United States. Mirex and chlordecone were most commonly used in the 1960s and 1970s. Mirex was used as a pesticide to control fire ants mostly in the southeastern part of the United States. It was also used extensively as a flame retardant additive under the trade name Dechlorane in plastics, rubber, paint, paper, and electrical goods from 1959 to 1972 because it does burn easily. Chlordecone was used to control insects that attacked bananas, citrus trees with no fruits, tobacco, and ornamental shrubs. It was also used in household products such as ant and roach traps. Chlordecone is also known by its trade name Kepone . All registered products containing mirex and chlordecone were canceled in the United States between 1977 and 1978. 

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