Plasticizers phosphate esters

Trimellitates are the esters of trimellitic anhydride (1,2,4-benzenetricarboxy-lic acid anhydride) and are noted for their low volatility. The most frequently used are trioctyl trimellitate (TOTM) and tri-isononyl trimellitate (TINTM). They are included in plastics which have to function at high temperatures for long periods and for PVC cable insulation in combination with phthalates. Phosphorous oxychloride reacts with various aliphatic and aromatic alcohols and phenols (triphenylphosphate) to produce triesters. Tricresyl phosphate was patented as a plasticizer for PVC in 1933, but was later found to be highly toxic and replaced. In addition to their role as plasticizers, phosphate esters, particularly triphenyl phosphate, function as flame retardants. 

Polymer/plasticizer Phosphate ester Minimum exposure time (sT Complete exposure time (s,y... 

Most phosphate esters are made from POCl and used as plasticizers (qv) and nonflammable hydrauHc fluids (qv). 

Most of the phosphate esters are used in the production of hydrauHc fluids (qv), plastic and elastomer additives, flame retardants (qv), oil stabilizers, pesticides (qv), and medicinal intermediates (see Surfactants). Some trialkyl phosphates, OP(OR)2, are outstanding solvents for nitrates, especially (UO2) (N02)2, and therefore are important in uranium processing (see Extraction). 

Phosphate Esters. The principal advantage of phosphate esters is the improved fire retardancy relative to phthalates. The fire performance of PVC itself, relative to other polymeric materials, is very good due to its high halogen content, but the addition of plasticizers reduces this. Consequendy there is a need, in certain demanding appHcations, to improve the fire-retardant behavior of dexible PVC. 

Plasticized PVC. Chlorinated paraffins are employed as secondary plasticizers with fire-retardant properties in PVC and can be used as partial replacements for primary plasticizers (qv) such as phthalates (1) and phosphate esters (2). 

Plasticizers. Addition of softeners to NBR improve tack and adhesion properties. The most common plasticizers are esters (dibutyl phthalate, tricresyl phosphate), ester gums, alkyd resins, etc. 

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... 

Robinson EC, Hammond BG, Johannsen FR, et al. 1986. Teratogenicity studies of alkylaryl phosphate ester plasticizers in rats. Fundam Appl Toxicol 7 138-143. 

Brominated phosphate heated in a glass tube in air at 300°C for 30 minutes remains a water-white liquid. This was compared with commercial bromine-containing flame retardants which melt they all turn color. The excellent color stability of this brominated phosphate ester makes it suitable for the high temperature processing of engineering plastics. 

Epoxy phosphate esters, 10 383-384 Epoxy plasticizers, for PVC polymers, 25 674... 

Mixed phosphate ester-titanium complexes, 25 92 Mixed plastics, reprocessing of,... 

Reduction of polymer flammability is of broad interest for applications ranging from plastics to textiles. For polyesters, given their inherent instability towards water at elevated temperatures, and the high temperatures of manufacture, many classes of flame-retardant (FR) agents, including most halogen-containing materials, are impractical. Phosphate esters, capable of incorporation into the polymer backbone, were pioneered by Hoechst AG, and continue to be the materials of choice [84, 85],... 

Castle, L., Mercer, A.J., Startin, J.R. and Gilbert, J. (1988a). Migration from plasticized films into foods. 3. Migration of phthalate, sebacate, citrate and phosphate esters from films used for retail food packaging, Food Addit. Contain., 5, 1, 9-20. 

Sometimes, addition of plasticizer imparts flame retardant characteristics in addition to other properties. Phosphate esters such as tris(2-ethyl hexyl) phosphate (TOP), tricresyl phosphate (TCP), chlorinated paraffin hydrocarbons etc. impart excellent flame retardant characteristics to many polymers. 

S 2.0, starch 0.5 chalk 0.3ps. The plastic props of the expl are lost if the phosphate ester is omitted]... 

Triphenylphosphate is a colorless, odorless, crystalline solid (mp, 49°C bp, 245°C). It is moderately toxic. A similar, but much more toxic, compound is tri-o-cresyl-phosphate (TOCP), an aryl phosphate ester with a notorious record of poisonings.3 Before its toxicity was fully recognized, TOCP was a common contaminant of commercial tricresylphosphate. Tricresylphos-phate is an industrial chemical with numerous applications and consists of a mixture of phosphate esters in which the hydrocarbon moieties are meta and para cresyl substituents. It has been used as a lubricant, gasoline additive, flame retardant, solvent for nitrocellulose, plasticizer, and even a cooling fluid for machine guns. Although modem commercial tricresylphosphate contains less than 1% TOCP, contaminant levels of up to 20% in earlier products have resulted in severe poisoning incidents. 

Plasticizers Phthalate esters, trialkyl phosphates, adipates, chlorinated paraffins, high molecular-weight polyesters, epoxy derivatives... 

Liquid chlorinated paraffins are the main halogen-containing fire-retardant additives used for poly(vinyl chloride) often in combination with a phosphate ester. In this case, the chlorinated paraffins have the secondary function of plasticizers. The thermal degradation mechanism of chlorinated paraffins is similar to that of poly(vinyl chloride), so in this case poly(vinyl chloride) stabilizers have also the secondary function to stabilize chlorinated paraffins. 

Phosphate esters (alkyl or aryl, or mixed) of phosphoric acid constitute an important family of organophosphorus flame retardants.25 Triethylphosphate, a colorless liquid boiling between 209°C and 218°C, and containing 17 wt % phosphorus, has been used commercially as an additive for polyester resins/laminates and in cellulosics. In polyester resins, it functions as a viscosity depressant as well as a flame retardant. Trioctylphosphate is employed as a speciality flame-retardant plasticizer for vinyl composites where low temperature flexibility is critical. It can be also included in blends, along with general purpose plasticizers, such as phthalate esters, to improve low temperature flexibility. 

When immobilized in a polymer-plasticizer matrix, (dppe)Pt S2C2(2-py) (CH2CH2OH), can be used for the rapid selective detection of volatile fluoro-, chloro-, and cyanophosphates (Table III, Fig. 10). As with many film immobilized lumiphores, the reactivity is controlled by the immobilizing matrix (39-44, 46, 50-52, 57, 58, 63, 75-77) Such an effect is seen as the sensitivity to phosphate esters increases as plasticizer (triethyl citrate, TEC) concentration increases in the cellulose acetate CA/TEC film (Table IV). 

---