Methylene-diphenylene diisocyanate

The major poly isocyanates used (2) are toluene diisocyanate (TDI) and the less volatile 4,4/-methylene diphenylene diisocyanate (MDI), which, because it is a crystalline solid in the pure form, has to be used in a relatively crude form. The crude polyisocyanate is a mixture of MDI variants that is conveniently a liquid product with a mean functionality greater than 2. The use of a pure, liquid diisocyanate, however, would enable polyurethanes to be formed having relatively enhanced physical properties (2) and would also greatly simplify processing by removing the need to use elevated temperatures, solvents, or isocyanate prepolymers as with MDI. 

Carr, R.H. Jackson, A.T. PreUminary MALDI-TOF and Field Desorption Mass Spectrometric Analyses of Polymeric Methylene Diphenylene Diisocyanate, Its Amine Precursor and a Model Polyedier Prepolymer. Rapid Commun. Mass Spectrom. 1998, 72,2047-2050. 

MC MDI MEKP MF MMA MPEG MPF NBR NDI NR OPET OPP OSA PA PAEK PAI PAN PB PBAN PBI PBN PBS PBT PC PCD PCT PCTFE PE PEC PEG PEI PEK PEN PES PET PF PFA PI PIBI PMDI PMMA PMP PO PP PPA PPC PPO PPS PPSU Methyl cellulose Methylene diphenylene diisocyanate Methyl ethyl ketone peroxide Melamine formaldehyde Methyl methacrylate Polyethylene glycol monomethyl ether Melamine-phenol-formaldehyde Nitrile butyl rubber Naphthalene diisocyanate Natural rubber Oriented polyethylene terephthalate Oriented polypropylene Olefin-modified styrene-acrylonitrile Polyamide Poly(aryl ether-ketone) Poly(amide-imide) Polyacrylonitrile Polybutylene Poly(butadiene-acrylonitrile) Polybenzimidazole Polybutylene naphthalate Poly(butadiene-styrene) Poly(butylene terephthalate) Polycarbonate Polycarbodiimide Poly(cyclohexylene-dimethylene terephthalate) Polychlorotrifluoroethylene Polyethylene Chlorinated polyethylene Poly(ethylene glycol) Poly(ether-imide) Poly(ether-ketone) Polyethylene naphthalate Polyether sulfone Polyethylene terephthalate Phenol-formaldehyde copolymer Perfluoroalkoxy resin Polyimide Poly(isobutylene), Butyl rubber Polymeric methylene diphenylene diisocyanate Poly(methyl methacrylate) Poly(methylpentene) Polyolefins Polypropylene Polyphthalamide Chlorinated polypropylene Poly(phenylene oxide) Poly(phenylene sulfide) Poly(phenylene sulfone)... 

The production of aniline is a major international business, carried on in the US, Europe and Asia, mainly for the conversion, by reaction with formaldehyde under acid-catalyzed conditions, into diaminodiphenylmethanes 9a, 9b and 9c, and then into isocyanates, mainly 4,4/-methylenebis(phenylisocyanate) (MDI, also known as 4,4 -methylene-di-paraphenylene isocyanate, 4,4 -diphenylmethane diisocyanate, methylene diphenylene diisocyanate and diisocyanato diphenyl methane) (9d), from which polyurethanes are produced. This accounts for well over 60% of total demand (Figure 1). Aniline is also used in bulk for the production of antioxidants and vulcanization accelerators for rubber. Some 15.5 million lbs. of cyclohexylamine are made each year mainly by catalytic hydrogenation of aniline. Half the demand is for use as a boiler water additive. Other major uses include in the manufacture of herbicides, plasticizers, emulsifying agents, dyes, dry-cleaning soaps, acid gas absorbents and, in Asia, cyclamate sweeteners. Apart from India, the use of aniline for dyestuff manufacture represents about 10% of demand. 

Polyurethanes are versatile polymers typically composed of polyisocyanates and polyols. By varying constituents, a broad range of thermosets and thermoplastics can be produced and used in different applications. Possible systems include high-strength, high-modulus, structural composites soft rubbers elastic fibers and rigid or flexible foams. Although isocyanates have the ability to form many different polymers, very few types are used in actual production. The most common diisocyanates are methylene diphenylene diisocyanate (MDI) and toluene diisocyanate (TDI). Of these, TDI is the most commercially important dimer. 

Isocyanates are formed by reacting phosgene with an appropriate hydrocarbon substrate. Many isocyanates are possible depending upon the hydrocarbon starting material. The commercially important polyurethanes are manufactured from toluene diisocyanate, based on toluene, and methylene diphenyl isocyanate, based on aniline. Both toluene diisocyanate (TDI) and methylene diphenylene isocyanate (MDI) can be used to manufacture foamed products, but only MDI is used as the primary feedstock for elastomeric polyurethanes. 

Synonyms 4,4 -diphenyl methane diisocyanate 4,4 -diisocyanodiphenylmethane MBI 4,4 -methylenediphenyl diisocyanate PMDI methylene bis(phenylisocyanate) diphenyl methane diisocyanate 4,4 -methylene bisphenyl isocyanate methylene diphenyl diisocyanate i,i -methylene bis(4-isocyanato)-benzene methylenebis(4-isocyanatobenzene) bis(p-isocyanatophenyl)methane i,i-methylenebis(4-isocyanatobenzene) bis(i,4-isocyanatophenyl)methane methylene bis(p-phenylene isocyanate) Caradate 30 Desmodur 44 4,4 diisocyanatodiphenylmethane Hylene M50 Isonate 125M Isonate 125MF methylene bis(p-phenyl isocyanate) methylene di-p-phenylene diisocyanate 4,4 -methylene diphenylene isocyanate Nocconate 300 methylene di-p-phenyl diisocyanate diphenylmethyl diisocyanate methylene bisphenyl isocyanate MDI... 

Two series of polyether polyurethanes (PU) based on hydroquinone bis (P-hydroxyethyl) ether (HQEE) or 1,4-butanediol (BDO) as a chain extender were prepared by the one step bulk polymerisation process. By varying the mole ratio of poly tetra methylene oxide (PTMO) extender (with Mn = 1000 and Mn = 2000) and 4,4 -diphenylene methane diisocyanate (MDI) the two series of HQEE (PUlOOOHj, PU 1000H2, PU2000Hj,... 

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