Triaryl flame-retardant plasticizer

Trialkyl esters of phosphonic acid exist ia two structurally isomeric forms. The trialkylphosphites, P(OR)2, are isomers of the more stable phosphonates, 0=PR(0R)2, and the former may be rearranged to resemble the latter with catalytic quantities of alkylating agent. The dialkyl alkylphosphonates are used as flame retardants, plasticizers, and iatermediates. The MichaeUs-Arbusov reaction may be used for a variety of compound types, including mono- and diphosphites having aryl as weU as alkyl substituents (22). Triaryl phosphites do not readily undergo the MichaeUs-Arbusov reaction, although there are a few special cases. 

More usually, the plasticizer component of the formulation is replaced by flame-retardant plasticizers such as liquid chlorinated paraffins, acting as secondary plasticizers up to 30 per cent of the original plasticizer content. As an associate plasticizer, phosphoric esters are often used. The appropriate flame-retardance is achieved by adding 1 or 2 phr. of phosphorus to the compound. More rigid or more flexible cold-resistant products can be formulated with triaryl or trialkyl phosphates, respectively. Halogenated phosphates may also reduce the flammability of plasticized PVC. 

Triaryl phosphate n. A synthetic-ester type plasticizer derived from isopropylphenol feedstock, useful as a flame-retarding plasticizer in vinyl plastisols. 

Isopropylphenol reacts with phosphorus oxychloride to produce triaryl phosphate (used by the rubber industry as a flame-retardant plasticizer). 

Phosphorus oxychloride reacts with mixed isopropylphenols to produce triaryl phosphate flame-retardant plasticizer. 

Phosphorus trichloride is used to produce phosphorus oxychloride to synthesize triaryl phosphate flame-retardant plasticizer used in rubber. 

Santiclzer 143 is a proprietary, modified triaryl phosphate ester, designed for use as a flame-retardant plasticizer for a variety of polymer systems. 

Alkyl diphenyl phosphate plasticizers can exert flame-retardant action in vinyl plastics by a condensed-phase mechanism, which is probably some sort of phosphoms acid coating on the char. Triaryl phosphates appear to have a vapor-phase action (29). 

Mixed esters, such as isopropylphenyl diphenyl phosphate and tcrt-butylphenyl diphenyl phosphate, are also widely used as both plasticizers/flame retardants for engineering thermoplastics and hydraulic fluids.11 These esters generally show slightly less flame-retardant efficacy, when compared to triaryl counterparts however, they have the added advantage of lower smoke production when burned. Some novel oligomeric phosphate flame retardants (based on tetraphenyl resorcinol diphosphate) are also employed to flame retard polyphenylene oxide blends, thermoplastic polyesters, polyamides, vinyls, and polycarbonates. 

Alkyl diaryl and triaryl phosphates have a synergistic action as plasticizers and as flame retardants. Phosphate plasticizers are prepared firom POCI3 and monofunctional alcohols or alkylated phenols. Industrial manufacturing necessitates the manipulation of HCl by-product, which is very corrosive and can cause undesirable side reactions. Because of their flame-retardant properties phosphate plasticizers are employed in fire-retardant apphcations such as cables and spread contract flooring. 

Flame retardants that are often nsed in polycarbonate/ABS plastics (such as in compnter indnstry) include nonhalogen triaryl phosphates, such as RDP [resorcinol bis (diphenyl phosphate)] and BDP [bisphenol A bis(diphenyl phosphate)]. As BDP has lower phosphorus content compared to that of RDP, more of it should be used to match the flammability performance of RDP. In one particular study using polycar-bonate-ABS alloy, 9% of RDP or 12.3% of BDP was employed and showed equal to each other and excellent flame retardant properties [8]. 

Fyrolflex RDP is a resorcinol bis(diphenyl phosphate). It is a liquid that is designed for use in engineering plastics such as polyesters, modified PPO as well as PC/ABS blends and HIPS. It has low volatility and good thermal stability, meaning it can outperform triaryl phosphates, such as triphenyl phosphate. Fyrolflex RDP is used either as a flame retardant or, in low doses, as a flow modifier. 

Alkyl Diphenyl Phosphates. These are products originally developed to provide improved low temperature flexibility, a fault of triaryl phosphate plasticizers in PVC (103). These phosphates generally provide slightly less flame-retardant efficacy but are generally superior to the triaryl phosphates in regard to smoke when the vinyl formulation is burned. Two commercial products of this family are 2-ethylhexyl diphenyl phosphate [1241-94-7], C20H27O4P, Ferro s SANTICIZER 141 or Akzo Nobel s PHOSFLEX 362, and isodecyl diphenyl phosphate [29761-21-5], C22H31O4P, Ferro s SANTICIZER 148 or Akzo Nobel s PHOSFLEX 390. A... 

TAP is used as a plasticizer in flame-retardant rubber compounds because the other plasticizers provide a fuel source that feeds a fire in the case of combustion. That is why many times this phosphate plasticizer is selected instead of other plasticizers. Recently, the use of triaryl phosphates has attracted attention again because of... 

Many times rubber compounds require a piasticizer. However, most plasticizers or processing oils hurt flame retardancy because they provide a fuel source to a potential fire if there is combustion. If a plasticizer must be used, the correct type of triaryl phosphate should function as both a plasticizer and a flame retardant in both the gas and condensed phases. 

Phenol reacts with propylene to produce mixed isopropylphenols, which are used to make triaryl phosphate plasticizer flame retardants used in rubber formulations. 

Phosphorus is oxidized into phosphorus pentoxide, which is used to make phosphorus oxychloride to produce triaryl phosphate plasticizer and flame retarder for rubber. 

Phosphorus pentoxide is used to produce phosphorus oxychloride, which is used to produce triaryl phosphate plasticizers that can impart some flame retardancy to rubber compounds. 

Santiclzer 154 plasticizer is a triaryl phosphate ester with flame-retardant properties suitable for use in a variety of polymer systems. 

Of this family of products, triaryl phosphates (TAP) and alkyl diaryl phosphates (ADP) are the two important categories of FR plasticizers for PVC. Trialkyl phosphates are considered too volatile for most vinyl processes, and are more commonly found in other applications, such as leveling agents or antifoam additives. In vinyl, TAP and ADP plasticizers are used to flame-retard thin films and laminates for articles such as wall covering, tarpaulins (transportation), and vinyl-coated furniture fabric. Another major application area is in vinyl for electrical insulation in wire and cable. In addition to these applications, phosphate esters are used as functional fluids for hydraulic equipment (metal industries, power generation, and aircraft hydraulic systems) and as additives in formulated lubricant systems. As flexible vinyl composites are usually defined by their additives, when formulated correctly, phosphate esters can help produce a very cost-efficient vinyl composite capable of very low smoke and flammabihty. In nearly all markets, phosphate esters are valued primarily for their FR properties, and the distinction from function and plasticization is sometimes obscured. 

With a recent push toward non-brominated flame retardants, phosphorus-based alternatives, such as phosphate esters, are used more frequently for various applications. Their use as plasticizers is also well known. However, their function as environmental stress crack agents of various thermoplastics is less well recognized. Two case studies, one - in which a triaryl phosphate was a component of the formulation, the other - in which it was migrating from an adjacent component illustrate some of the problems with their use. Fractographic analysis and various analytical techniques were used to determine a root cause of each of the two failures. 

The mechanism of burning for polymers is believed to take place through thermal pyrolysis of the solid plastic to produce gases that act as fuel for the fire (45). Fire retardants work in both the condensed and the vapor phase to interrupt melting of the polymer and burning of the gases. Triaryl phosphates function well in the vapor phase. Alkyl aryl phosphates are believed to decompose in the flame front to form polyphosphoric acid, which stays in the condensed phase to form char, which reduces flammability and smoke evolution (46. 47). 

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