Triphenylmethane triisocyanate

Polyisocyanates, particularly triphenylmethane 4,4, 4"-triisocyanate, are used for the bonding of rubber to rubber, metals, glass and synthetic fibres. They may be used in rubber-containing cements or, in the case of triphenylmethane triisocyanate, alone. 

Polyisocyanates. Whereas any standard, generally difiinctional, polyisocyanate, but preferably toluene diisocyanate (TDI) and methylenediphenyl diisocyanate (MDI), may be used for the production of polyurethane resins, only polyisocyanates with low vapor pressures at room temperature, such as MDI and its homologues, the reaction product of trimethylol propane with TDI, and triphenylmethane-4,4, 4"-triisocyanate, are recommended as hardeners for adhesives for reasons of industrial hygiene. 

Benzene, 1,1, r-methylidynettis(4-isocyanato- DesmiHlui RE EINECS 219-351-8 Methylidynetri-p-phenylene triisocyanate Triphenylmethane triisocyanate Triphenyl-methane-4,4, 4-... 

Isocyanates are used as a cross-linker in EPI adhesive systems. Theoretically, any isocyanate with two or more NCO groups would be suitable. In practice two main parameters are important for the choice of isocyanate The volatility and reactivity of the isocyanate [1, 12]. The use of isocyanates with low volatility, low vapor pressure, is preferred to minimize the health risks concerned with the use and handling of the isocyanate. Isocyanates that are typically used, or have been used, as cross-linkers in EPI adhesive systems are based on the following isocyanate monomers toluene diisocyanate (TDl), diphenylmethane diisocyanate (MDl), hexamethylene diisocyanate (HMDI), 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (IPDI) and triphenylmethane-triisocyanate (TTl)... 

Triphenylmethane triisocyanate (Desmodur R), a 20 % solution in methylene chloride. 

Unvulcanized rubber (sulphur-crosslinked) mixes are freshly coated with a 20% solution of 4,4, 4"-triphenylmethane triisocyanate (Desmodur R) or methylene chloride. After drying, the rubber is vulcanized in contact with a cleaned metal surface and a strong bond results. The reverse procedure is also satisfactory. For example, by this technique heat-, fatigue-, impact-, oil- and solvent-resistant bonds can be obtained between metals and elastomers by press or hot-air curing the green freshly milled or calendered... 

ADHESION VALUES BETWEEN VARIOUS RUBBERS AND METALS USING 4,4, 4"-TRIPHENYLMETHANE TRIISOCYANATE AS BONDING AGENT (DIRECT TENSION TEST)... 

Elastomer coatings may be adhered to synthetic fibre fabrics and other materials by diisocyanates which are applied directly to the fabric, usually as a solution (typically of 2% concentration) in toluene or methylene chloride or some similar non-reactive solvent, by dipping, spraying, roller coating and then drying. After this process the elastomer coating is applied to the treated fabric. Typical diisocyanates used for this purpose are MDI and 4,4, 4"-triphenylmethane triisocyanate (Desmodur R). 

In bonding strong substrates, and if solvent and greater heat resistance are required in the adhesive bond, then the Desmocolls may be mixed with appropriate amounts of isocyanates such as TDI,4,4, 4"-triphenylmethane triisocyanate (Desmodur R) or Desmodur RF (Fig. 8.7), which is thiophosphoric acid (p-isocyanatophenyl ester) used as a 20% solution in methylene chloride. 

Polyurethanes are formed in the reaction of isocyanates with polyols. The most important commercial aromatic isocyanates are toluenediisocyanate (TDI), diphenylmethane diisocyanate (MDI) and naphthalene diisocyanate (NDI), while the important aliphatic isocyanate is hexamethylene diisocyanate (HDI). Cycloaliphatic isocyanates of industrial importance are isophorone diisocyanate (IPDI) and hydrogenated MDI (HMDI). A number of triisocyanates, such as triphenylmethane triisocyanate, are used in coatings and adhesives. 

Crosslinking reagent, triphenylmethane triisocyanate (TTI), provided by Mobay Chemical Company, was first precipitated by adding n-heptane to a methylene chloride solution of TTI under N2 atmosphere. Repeated vacuum distillation (2-4 times) produced a pale pink viscous liquid, which was the finally purified TTI The functionality of TTI was determined by a modified ASTM method. ... 

Ill) Desmodur R — triphenylmethane-"-triisocyanate — a 20% solution in methylene chloride. 

Triphenylmethane-p,p, p"-triisocyanate. See Triphenyl methane 4,4, 4"-triisocyanate Triphenylphosphane. See Triphenyl phosphine Triphenyl phosphate CAS 115-86-6 EINECS/ELINCS 204-112-2 Synonyms Phosphoric acid, triphenyl ester ... 

X) Leukonat adhesive—triphenylmethane-p,/ p "-triisocyanate—a 20% solution in di-chloroethane. ... 

Crosslinkers. Polyisocyanates with functionality greater than two (such as p, p", p " -triisocyanate triphenylmethane, thiophosphoric acid tris (p-isocyanatephenyl) ester) can be added to improve specific adhesion and heat resistance of the polyurethane adhesives (especially those with slower crystallization rate). Most of them have 20-30 wt% solids, 5.4-7 wt% free NCO and the most common solvent is ethyl acetate. 5-10% polyisocyanate is generally added in the adhesive solution just before appHcation on the substrate, and it acts as cross-linking agent. Since all isocyanates react with the residual hydroxyl groups on the polyurethane, in solution they all yield adhesive systems with a limited pot life (1-2 h to several days). Addition of polyisocyanate improves the spotting tack and heat activation of the freshly dried adhesive films, but after several days they lose their capacity to be reactivated. 

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