Diisocyanate methane

NR can be cross-linked by a blocked diphenyl methanes diisocyanate to produce urethane crosslinks. The cross-linking agent dissociates into two quinonedioxime molecules and one diphenyl methane diisocyanate. The quinone reacts with the rubber via a nitroso group and forms cross-links via diisocyanato group. The performance of this system in NR is characterized by excellent age resistance and outstanding reversion resistance. 

Figure 7. Dependence on the gel fraction, molar ratio of OH to NCO groups, rjj, for poly(oxypropylene) (POP) triol -4,4 -diphenyl-methane diisocyanate (HDI) net-...

Tanser AR, Bourke MP, Blandford AG Isocyanate asthma respiratory symptoms caused by diphenyl-methane-diisocyanate. Thorax 2 -. 

PBX-9011-02 HMX 90 Sc Estane (Trademark of B.F, Goodrich Chemical Co for polyester urethane of adipic acid 1,4-butanediol, diphenyl methane diisocyanate) 10%... 

International Isocyanate Institute. 1990. Biodegradation of toluene diisocyanate and diphenyl methane diisocyanate. EPA/OTS doc 86-870000646. 

Rosthauser et al. (4) used l-methyl-3-phospholene-l-oxide to prepare and isolate oligomeric diisocyanates containing dicarbodiimides using 4,4 -diphenyl-methane diisocyanate. Diisocyanates containing dicarbodiimides were also prepared by Takahashi et al. (5) using 3-methyl-l-phenyl-2-phospholene-l-oxide as the reaction catalyst. 

Abbreviations PTMA poly(tetramethylene adipate) PEA poly(ethylene adipate) MDI diphenyl-methane diisocyanate BD butane diol PAN polyacrylonitrile Ar polyarylate OBU oligobutadiene-urethane... 

Sulfo group-containing poly(amide imide) semipermeable membrane 35 from trimellitic anhydride sodium 3,5-dicarboxybenzenesulfonate, and 4,4 -diphenyl-methane diisocyanate have been prepared 90>. A 110 p-thick membrane gave water permeation 5601/m2 day and salt rejection 99.0% (0.5% aqueous NaCl solution, 25 °C, 42 kg/cm2), while a trimellitic anhydride-4,4 -diphenylmethanediisocyanate copolymer membrane gave 30 1/m2 day and 98.2%, respectively. 

A Hexam thylene diisocyanate B 4,4 -dipheny,]methane diisocyanate. 

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,... 

The dynamic mechanical properties of three epoxy resins cured with diphenyl-methane diisocyanate (MDI) are shown in Fig. 15. Since these resins consist of many bulky cyclic structures, Tg (a-dispersion) is above 200 °C and the transition region is wide. In the DEN 431 —L-MDI resin, Tg is higher than 300 °C. The resin is expected to be highly heat-resistant51). 

Dozens of isocyanate functional compounds have been synthesized, but only a few find much use in urethane structural adhesives. The choices are largely dictated by a combination of performance, price, and safety considerations. Most of the materials used in adhesives are derived from the aromatic isocyanates, toluene diisocyanate (TDI) and 4,4 -diphenyl-methane diisocyanate (MDI). 

The saturated analogue of MDI, 4,4 -dicy-clohexyl methane diisocyanate, has found limited use as an aiphatic isocyanate in adhesives. This material is known by a variety of names including Desmodur W (Bayer), hydrogenated MDI (or HMDI or Hl2MDI), reduced MDI (RMDI), and saturated MDI (SMDI), It is a low-viscosity liquid with a fairly high vapor pressure, so it too must be handled with care. In adhesive compositions, the diisocyanate usually is used to make an isocyanate functional prepolymer by reacting excess diisocyanate with a hydroxyl or amine functional polymer such as a polyester diol. 

Because it contains two saturated six-member rings, 4,4 -dicyclohexyl methane diisocyanate can exist in three isomeric forms, in which the orientations of the NCO groups with respect to the rings and each other are different. The trans-trans isomer is a solid at room temperature so that over time this isomer can precipitate from the remaining liquid isomers. Samples of 4,4 -dicyclohexyl methane diisocyanate that have been stored at cool temperatures for a while often have a solid layer of trans-trans precipitate in the bottom. 

A rigid, foamed crosslinked PUR, usually with closed cells, is formed by the reaction of a diisocyanate and often methane diisocyanate (MDI) or polymeric MDI with polyester or more usually with a polyether polyol. Foaming may result from the water, which reacts with isocyanate groups to form carbon dioxide but is usually the result of using other... 

The IPNs prepared were composed of a rubbery polyurethane and a glassy epoxy component. For the polyurethane portion, a carbodiimide-modified diphenyl-methane diisocyanate (Isonate 143L) was used with a polycaprolactone glycol (TONE polyol 0230) and a dibutyltin dilaurate catalyst (T-12). For the epoxy, a bisphenol-A epichlorohydrin (DER 330) was used with a Lewis acid catalyst system (BF -etherate). The catalysts crosslink via a ring-opening mechanism and were intentionally selected to provide minimum grafting with any of the polyurethane components. The urethane/epoxy ratio was maintained constant at 50/50. A number of fillers were included in the IPN formulations. The materials used are shown in Table I. 

Isonate 143L Carbodiimide-modified diphenyl methane diisocyanate, functionality=2.1 Upjohn Co. 

DIPHENYLMETHANEDIAMINE see MJP750 4,4 -DIPHENYLMETHANEDIAMINE see MJQOOO DIPHENYL METHANE DIISOCYANATE see MJP400 4,4 -DIPHENYLMETHANE DIISOCYANATE see N5P400... 

Feng and Waldman used 4,4 -diphenylmethane diisocyanate. The polyol is either 2000 or 4000 molecular weight polypropylene glycol (PPG) and the catalyst is dibutylin dilaurate (DBTOL). The NOC-terminated urethane prepolymers are made in the usual way by reacting an excess of methane diisocyanate with PPG in the presence of DBTDL at an NCO OH ratio of 1.4 2.0. The reactions are run at 70°C for about 3 h to reach a constant percentage of NCO. 

A Polyester and a Polyurethane. A segmented polyether-polyurethane sample (UET46-1) was synthesized in one step from 4-4 diphenyl methane diisocyanate, 1-4 butanediol and poly(tetra-methylene ether)glycol ... 

Richter and Macsoko (1980) describe the chemoviscosity of a reactive polyurethane (4,4 -diphenyl methane diisocyanate, polyester triol and dibutyltin dilaurate catalyst) reasonably well by the following model ... 

Vibrathane B605 A prepolymer based on diphenyl-methane diisocyanate (MDI) and poly-tetramethylene glycol 3.02 1333 Uniroyal... 

Thus, from high MW diols (MW = 1000-4000 daltons) polyethers (polyalkyleneoxides, polytetrahydrofuran (PTHF)), polyesters, polycarbonates (PC), polybutadienes, etc., by the reaction with diisocyanates [toluene diisocyanate (TDI), or pure diphenyl methane diisocyanate (MDI)], high MW linear polyurethanes are obtained (no crosslinking), with high elasticity (polyurethane elastomers, spandex fibres, some adhesives and sealants, etc). 

While the use of plastics in refirigerators is well established, product development has led to replacement of some of the conventional plastics with newer ones of improved properties. For insulation rigid polyurethane foam has, on the whole, replaced fiberglass in cabinets and doors. In this application, diphenyl-methane diisocyanate (MDI), which has lower vapor pressure than toluene diisocyanate (TDI), is now preferred. 

---