Methylene diisocyanate

A different diisocyanate used in polyurethane synthesis is methylene diisocyanate (MDI), which is prepared from aniline and formaldehyde. The diamine product is reacted with phosgene to get MDI. 

PMDA, 20 266. See also Polymeric methylenedianiline (PMDA) PMDA-ODA, gel casting of, 20 271-272 PMDA-ODA structures, 10 214 PMDI polymeric isocyanate, 25 456, 457, 462. See also Polymeric methylene diisocyanate resins (PMDI) rigid polyurethanes from, 25 471-472 PMF/PMUF resins, 15 779 PMF resins, hardening of, 15 781 PMMA ionomer, 4DA and, 14 479 PM optimization (PMO), 15 466 PM process, 21 50 Pneumatic classification, 22 288 health and safety factors related to,... 

Lithium aluminum hydride Lithium hydride Methyl isocyanate Methylaluminum sesquibromide Methylaluminum sesquichloride Methyldichlorosilane Methylene diisocyanate Methylpentaldehyde Methyltrichlorosilane Mono-(trichloro)-tetra-(mono-potassium dichloro)-penta-s-triazinetrione, dry Monochloro-s-triazinetrione acid Octadecyltrichlorosilane Phenyl trichlorosilane Phosphorus oxychloride Phosphorus pentachloride Phosphorus pentasulfide... 

Uses Preparation of phenol, 4-chlorophenol, chloronitrobenzene, aniline, 2-, 3-, and 4-nitro-chlorobenzenes carrier solvent for methylene diisocyanate and pesticides solvent for paints insecticide, pesticide, and dyestuffs intermediate heat transfer agent. 

The aerosol technique can also be used to produce polymer colloids by addition polymerization. Thus, when droplets of toluene-2,4-diisocyanate (TD1) or 1,6-hexa-methylene diisocyanate (HDI) were brought into contact with ethylenediamine (EDA) vapor (in the apparatus shown in Fig. 1.5.3) spherical polyurea particles with modal diameters of 1-3 p,m were formed. The entire process, i.e., the formation of droplets and the polymerization, was carried out at moderate temperatures (<80°C)... 

We collaborated with Professor Palligamai Vasudevan of the Chemical Engineering Department of the University of New Hampshire on a study of immobilization of lipases on CoFoam. Immobilization was performed at the Hydrophilix facility in Portland, ME. Approximately 2 g lipase (from porcine pancreas and Mucor miehei) were stirred into 500 ml deionized water. The enzyme solution was emulsified with an equal volume of a methylene diisocyanate (MDI)-based hydrophilic polyurethane... 

Polyurethanes. Metal-containing polyurethanes have been synthesized by poly-condensing Co2+, Cu2+ salts of mono(hydroxyethyl) phthalate with hexa-methylene diisocyanate and tolylene diisocyanates [47] (Fig. 19). 

Methylenebutanal oxime, see 2-Ethylacryladehyde oxime, 1927 Methylene diisocyanate, see Diisocyanatomethane, 1076 Methylenedilithium, 0400... 

Following the early developments using NDI, it was found that by using TDI instead, a far more stable prepolymer could be made. Stable prepolymers are normally made using either polyesters or polyethers that have been reacted with a slight excess of a diisocyanate such as toluene diisocyanate (TDI) or methylene diisocyanate (MDI). Provided the storage is moisture free, the stable prepolymer may be kept for months before use. The polyurethane is prepared by chain extension with diols or diamines. 

The polyol, the chain extender, and any catalysts are mixed and stored as a separate item. The second item, the diisocyanate prepolymer, is kept as a "B" part until the material is ready for use. When the two parts are mixed, the chain extension and cross-linking take place simultaneously. Methylene diisocyanate and a catalyst such as an organic tin or bismuth salt provide the... 

Monochlorobenzene is a flammable clear liquid (fp, -45"C bp, 132°C) used as a solvent, solvent carrier for methylene diisocyanate, pesticide, heat transfer fluid, and in the manufacture of aniline, nitrobenzene, and phenol. The 1,2- isomer of dichlorobenzene (ortho-dichlorobenzene) has been used as a solvent for degreasing hides and wool and as a raw material for dye manufacture. The 1,4- isomer (para-dichlorobenzene) is also used in dye manufacture and as a moth repellant and germicide. All three isomers have been used as fumigants and insecticides. The 1,2- and 1,3-(meta) isomers are liquids under ambient conditions, whereas the 1,4- isomer is a white sublimable solid. Used as a solvent, lubricant, dielectric fluid, chemical intermediate, and formerly as a termiticide, 1,2,4-trichlorobenzene is a liquid (fp, 17°C bp, 213°C). 

Uses of phosgene include the manufacture of toluene diisocyanate, methylene diisocyanate, and polycarbonate resins. 

Nonemulsifiable and emulsifiable polymeric methylene diisocyanates (Desmodur VP PU 1520 A 31 and 1520 E, Messrs. Bayer, West Germany) were combined with maize starch and solutions of tannin extract or protein. 

Proton NMR studies were utilized to determine the kinetics of the degradation process by quantifying the relative amount of oxidation of the MDI-units in Estane at different aging times and temperatures. Identification of the oxidation degradation product and of the associated NMR resonances is based on earlier work using isotopic enrichment 11). In this previous study, N enriched Estane analogues and MDI model compounds were synthesized in which the nitrogens of the urethane methylene diisocyanate-unit (MDI-unit) were... 

The first commercial aliphatic diisocyanate to be available is 1,6-hexa-methylene diisocyanate (HDI). It is a colourless liquid with a boiling point of 127 C at 10 mm Hg. It is less reactive than either TDI or MDI, but in the presence of a catalyst the rate of reaction is enhanced. The use of HDI leads to urethane polymers with better resistance to discolouration, hydrolysis and heat degradation than has TDI (Frisch, 1969). A number of aliphatic diisocyanates have become available commercially. These aliphatic diisocyanates have been reported to give excellent colour stability. Some important ahphatic diisocyanates are illustrated in Figure 2.16. 

Use Phenol, chloronitrobenzene, aniline, solvent carrier for methylene diisocyanate, solvent, pesticide intermediate, heat transfer. 

Usually, methylene diisocyanate (MDI) is used with m-phenyl diamine (m-PDA) with hard (aromatic amine) or- soft (amine terminated polyether with MW of 500-5400 Daltons) chain extenders. With optimized formulations and extruder-mold conditions, cycle times of 3 to over 5 min can be obtained. With the use of internal mold release agents, the cycle time can be reduced to less than 2 min. Typical RIM operations for the production of automotive parts can run down to 1-min cycle time. These products range from the softer bumper covers to stiffer vertical body panels, such as fenders, doors, and quarter panels. 

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