Plasticizers trimellitate esters

A.4.2 Wimellitates Except for a very few highly specialized and expensive esters, the trimellitate ester plasticizers currently represent the state of the art in low-volatility monomeric plasticizers. As in the case with phthalates, the branched-chain trimellitate esters are less expensive than the straight-chain/linear trimellitates. Linear trimellitates offer improved low-temperature flexibility and processabihty over their branched counterparts. 

TABLE 7.8 Performance Comparisons of Trimellitate Ester Plasticizers in PVC at 50 phr and 70A Hardness... 

Plasticizers. Monomeric (mol wt 250—450) plasticizers (qv) are predominantly phthalate, adipate, sebacate, phosphate, or trimellitate esters. Organic phthalate esters like dioctyl phthalate (DOP) are by far the most common plasticizers in flexible PVC. Phthalates are good general-purpose plasticizers which impart good physical and low temperature properties but lack permanence in hot or extractive service conditions and are therefore sometimes called migratory plasticizers. Polymeric plasticizers (mol wt up to 5000 or more) offer an improvement in nonmigratory permanence at a sacrifice in cost, low temperature properties, and processibility examples are ethylene vinyl acetate or nitrile polymers. 

Benzenetricarboxylic acid, tris 2-ethyltiexyl) ester BRN 2683525 CCRIS 4733 EINECS 222-020-0 Hatcol 200 HSDB 6145 Kodaflex TOTM Monosizer W710L Morflex 510 PX-388 Staflex TOTM TOTM Tri-(2-ethylhexyl)trimellitate Trimex T 08 Tris(2-ethylhexyl) trimellitate. Primary plasticizer used in vinyl film and vinyl-coated fabrics. Oil bp = 414° d = 0.9890 LD50 (mus orl) >60 g/kg. Aristech Eastman Chem. Co. 

In a flexible PVC compound the trimellitates are less volatile and have improved thermal stability over the phthalate and polymeric plasticizers. Their plasticizing effectiveness and compatibility are similar to phthalates. They offer better moisture and water resistance than the phthalates or polymeric plasticizers. Large volumes of trimellitate esters are used in 90°C and 105°C UL rated insulation compounds. Because of their extraction and migration resistance, thermal stability, and low volatility, the trimellitates are used in conjimction with 9IIP and DUP in automotive interior trim applications where windshield fogging is an issue. 

Phthalic anhydride or trimellitic anhydride are converted into esters by reactions with alcohols as shown in Figure 8. Phthalic anhydride is produced cheaply and in large volume from oxidation of ortho-xylene. The largest use of phthalate esters is in the plasticizer market. Only a small fraction of its production is consumed by the synthetic lubricants market. Phthalate esters generally have superior hydrolytic stability than adipic esters because the ortho di-ester groups are electronically less available and sterically more hindered. However, they have lower Vis, 50-70, because of their high polarity and the presence of branched alcohol chains. They are used in special industrial oil applications where VI is not a critical parameter. Trimellitate esters are specialty products and relatively expensive. They are of high viscosity and usually are more resistant to oxidation than adipic esters. 

Trimellitic anhydride is quite a young molecule for Polynt. Its industrial production started in the Scanzorosciate site in Italy in 1994 after a six-year project devoted to develop the technology and catalyst formulation. From 2007 a similar technology and catalyst have been used in Polynt s Changzhou plant in China, where, as in Italy, TMA is further transformed into trimellitate esters, utilized as special plasticizers. 

Because of the lower volatility of DIDP and DPHP relative to other GP plasticizers, these two plasticizers are also sometimes considered low-volatility plasticizers. For automotive interior products the plasticizers DEHP, DINP, DEHTP, DC9CH, citrates, benzoates, as well as many of the phthalate alternatives would fail many interior emission or fogging requirements while DIDP and DPHP, along with trimellitate esters and the linear phthalates L9P and L91P, would pass. 

Trimellitate esters are used as primary plasticizers in those applications where greater permanence is required. Tliese esters, prepared by the esterifica-... 

Trimellitate esters were first introduced in the late 1960s. These plasticizers rapidly gained acceptance in higher-temperatore PVC wire insulation. The lower migration rates of trimellitates have created additional demand for these products in gaskets. ... 

The replacement of the more volatile plasticizers with low-fogging plasticizers such as DIDP, DPHP, L9P, 91 IP, DUP, and trimellitate esters has greatly reduced the fogging problem, to the extent that analyses of the residue collected from flie interior windows rarely detect the presence of phthalates. Indeed, Howick reports... 

Ch1orocarhony1trime11itic acid 1,2-anhydride [1204-28-0] (9), is used in the preparation of esters and amide—imide polymers. TriaHyl trimellitate [2694-54-4] (10) is used as a cross-linking or co-curing agent for ethylene-derived mbbers and plastics. 

Low Temperature Performance. The ability of plasticized PVC to remain dexible at low temperatures is of great importance in certain applications, eg, external tarpaulins or underground cables. For this property the choice of the acid constituent of the plasticizer ester is also important. The linear aliphatic adipic, sebacic, and azeleic acids give excellent low temperature flexibility compared to the corresponding phthalates and trimellitates (Fig. 3). 

Plasticizers. Plasticizers are materials that soften and flexibilize inherently rigid, and even brittle polymers. Oiganic esters are widely used as plasticizers in polymers (97,98). These esters include the benzoats, phthalates, terephthalates, and trimellitates, and aliphatic dibasic acid esters. For example, triethylene glycol bis(2-ethylbutyrate) [95-08-9] is a plasticizer for poly (vinyl butyral) [63148-65-2], which is used in laminated safety glass (see Vinyl polymers, poly(vinyl acetals)). Di(2-ethylhexyl)phthalate [117-81-7] (DOP) is a preeminent plasticizer. Variation of acid and/or alcohol components) modifies the efficacy of the resultant ester as a plasticizer. In phthalate plasticizers, molecular sizes of the alcohol moiety can be varied from methyl to tridecyl to control permanence, compatibility, and efficiency branched (eg, 2-ethylhexyl, isodecyl) for rapid absorption and fusion linear (C6—Cl 1) for low temperature flexibility and low volatility and aromatic (benzyl) for solvating. Terephthalates are recognized for their migration resistance, and trimellitates for their low volatility in plasticizer applications. 

Another important development in the early sixties was the commercialization of trimellitic anhydride (TMA). Monohydric alcohol triesters of TMA were shown to have outstandingly low volatility while overcoming the poor low temperature properties of polymeric-type plasticizers. In addition, the TMA esters were lower in cost than the polymeries - particularly when volume cost was considered. 

Pseudocumene is an item of commerce, and comprises approximately 15% of the heavy gasoline fraction. Its major use is for oxidation to trimellitic acid or its anhydride. These compounds have a number of uses, but the major ones are to form temperature resistant plasticizers for pvc (e.g. as the trioctyl ester), to form high performance plastics (e.g. the polyamide-imides),... 

The pyromellitate esters are also good low mobility plasticizers, and have seme advantages over the trimellitates (e.g. a still lower nobility) and some disadvantages (e.g. the esters are more viscous, and gelling is more... 

Poly(ester-imide)s useful as molding plastics are made from terephthalic acid, trimellitic anhydride, 4-(aminomethyl)cyclohexanemethanol, and 1,4-cy-clohexanedimethanol [244]. Blends of this poly(ester-imide) with polycarbonate are also patent protected [245]. An amorphous polymer containing units derived from N-3-hydroxyphenyl trimellitimide and units derived from p-hy-droxybenzoic acid [246] and another having units derived from 9,9-bis(4-ami-nophenyl)fluorene [247] have similar claims. 

ADK CIZER C-8 1,2,4-Benzenetricarboxylic acid, trioctyl ester Benzene tricarboxylic acid, trioctyl ester Diplast TM Diplast TM8 EINECS 201-877-4 HSDB 5263 JayBex TOTM Kodaflex TOTM Nuopiaz 6959 PX 338 TOTM Tri (2-ethylhexyl) trimellitate Tri-n-octyl trimellitate Trimex N 08 Trioctyl trimellitate Nuopiaz TOTM Palatinol TOTM Plasthall TOTM PX-338 Staflex TOTM Uniflex TOTM. Plasticizer Solid d = 0.989 bp = 414°. Exxon ExxonMobil Chem. Co. 

Nontoxic Pi used in inhibited plastics include (Table 6.2) mineral oils, polyatomic alcohols (glycerin), higher fatty acids (oleic acid), esters of aliphatic carbonic acids (sebacates) and trimellitic acids (mellitates). 

Polymer plasticization can be achieved either through internal or external incorporation of the plasticizer into the polymer. Internal plasticization involves copolymerization of the monomers of the desired polymer and that of the plasticizer so that the plasticizer is an integral part of the polymer chain. In this case, the plasticizer is usually a polymer with a low Tg. The most widely used internal plasticizer monomers are vinyl acetate and vinylidene chloride. External plasticizers are those incorporated into the resin as an external additive. Typical low-molecular-weight external plasticizers for PVC are esters formed from the reaction of acids or acid anhydrides with alcohols. The acids include ortho- and iso-or terephthalic, benzoic, and trimellitic acids, which are cyclic or adipic, azeleic, sebacic, and phosphoric acids, which are linear. The alcohol may be monohydric such as 2-ethylhexanol, butanol, or isononyl alcohol or polyhydric such as ethylene or propylene glycol. The structures of some plasticizers of PVC are shown in Table 9.1. 

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