Desmodur

The polyamide copolymer of dodecanoic acid with methylenedi(cyclohexylamine) (MDCHA, PACM) was sold as continuous filament yam fiber under the tradename QIANA. As late as 1981, over 145,000 t was produced using high percentages, typically 80%, of trans, trans MDCHA isomer. The low melting raffinate coproduct left after t,t isomer separation by fractional crystallisation was phosgenated to produce a Hquid aUphatic diisocyanate marketed by Du Pont as Hylene W. Upon terrnination of their QIANA commitment, Du Pont sold the urethane intermediate product rights to Mobay, who now markets the 20% trans, trans—50% cis, trans—30% cis, cis diisocyanate isomer mixture as Desmodur W. In addition to its use in polyamides and as an isocyanate precursor, methylenedi (cyclohexyl amine) is used directiy as an epoxy curative. The Hquid diamine mixture identified historically as PACM-20 is marketed as AMICURE PACM by Anchor Chemical for performance epoxies. 

Methylenedi(cyclohexyhsocyanate) (45) [5124-30-1] (MDCHl, Desmodur W) is the dominant derivative of MDCHA and is used in light-stable urethanes. Polyurethane physical properties are dependent on the diamine geometric isomer composition used for the derivative diisocyanate which reacts with diol (87). 

Ionic polymers are also formulated from TDI and MDI (43). Poly(urethane urea) and polyurea ionomers are obtained from divalent metal salts of /)-aminohen2oic acid, MPA, dialkylene glycol, and 2,4-TDI (44). In the case of polyureas, the glycol extender is omitted. If TDI is used in coatings apphcations, it is usually converted to a derivative to lower the vapor pressure. A typical TDI prepolymer is the adduct of TDI with trimethyl olpropane (Desmodur L). Carbodiimide-modified MDI offers advantages in polyester-based systems because of improved hydrolytic stabihty (45). Moisture cure systems based on aromatic isocyanates are also available. 

Desmodur RF thiophosphonic acid tris(/t-isocyanatophenyl) ester 97... 

A prepolymer is made first by charging Pluracol E2000 [1000.0 g, 1.0 eq., poly(ethylene oxide), 56 OH, BASF] to a suitable container equipped with a mechanical stirrer and a nitrogen gas inlet. Flush the container with dry nitrogen and add Desmodur W (264.0 g, 2.0 eq., 4,4 -methylene-bis(cyclohexyl isocyanate), 31.8% NCO, Bayer). While maintaining a positive N2 pressure on the reaction mixture, stir and heat at 80°C for 2 h. Cool the product to room temperature and check the NCO content (theory = 3.32 %). It might be necessary to warm the highly viscous prepolymer to take samples for titration. To a portion of this prepolymer (250.0 g, 0.2 eq.), add Dabco T-12 (0.25 g, dibutyltin dilaurate,... 

Example 7. Solvent-Borne, One-Component, Moisture-Cure, Aliphatic Polyurea Coating. This example is of a more traditional one-component coating formulation using a volatile solvent as a diluent. The active ingredient is a modified HDI, Desmodur N-75 BA from Bayer. 

Model networks were prepared using hydroxyl terminated polymer and isocyanates, (a) Bifunctional hydroxyl terminated polybutadiene (Butarez, from Phillips Petroleum) was crosslinkined with tris (p-isocyanatophenyl)-thiophosphate (Desmodur RF, from Mobay Chemical Co.). This crosslinked... 

Synonyms AI3-015101 BRN 0744602 CCRIS 3742 Desmodur T80 2,4-Diisocyanato-l-methylbenzene Diisocyanatoluene 2,4-Diisocyanotoluene Hylene T Hylene TCPA Hylene TLC Hylene TM Hylene TM-65 Hylene TRF Isocyanic acid, methylphenylene ester Isocyanic acid, 4-methyl-/ 3-phenylene ester 4-Methylphenylene diisocyanate 4-Methylphenylene isocyanate Mondur TD Mondur TD-80 Mondur TDS Nacconate 100 NCI-C50533 Niax TDI Niax TDI-P NSC 4791 NSC 56759 RCRA waste number U223 Rubinate TDI 80/20 TDI 2,4-TDI TDI-80 Toluene 2,4-diisocyanate Tolyene-2,4-diisocyanate Tolylene-2,4-diisocyanate 2,4-Tolylene diiso-cyanate /n-Tolylene diisocyanate UN 2078. 

Preparation of P(UA)-2 Coating. In lOOg of PBH solution, 45g of Desmodur N-lOO and Ig of Dabco XDM catalyst were added. Using a doctor blade, clear films were drawn on glass and steel panels and were cured using the same conditions as in the case of P(UA)-1. 

HDI is the common name for hexamethylene diisocyanate. It is also known as 1,6-hexamethylene diisocyanate, 1,6-diisocyanatohexane, Mondur HX, and Desmodur H. It is a pale yellow liquid with a strong odor. HDI is found in hardening agents for automobile paints. 

Registered trade name(s) Desmodur N-75 Desmodur N-IOO Desmodur N-3200 Desmodur N-3300 Desmodur N3390 ... 

Ferguson JS, Schaper M, Alarie Y. 1987. Pulmonary Effects of a Polyisocyanate Aerosol Hexamethylene Diisocyanate Trimer (HDlt) or Desmodur-N (DES-N). Toxicol Appl Pharmacol 89(3) 332-346. 

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