Naphthylene 1,5-diisocyanate

Naphthylene 1,5-diisocyanate (NDI) is prepared from naphthalene as follows ... 

Naphthylene 1,5-diisocyanate is a solid, m.p. 128°C. It has a lower vapour pressure than tolylene diisocyanate and is therefore less toxic in use it does, however, have sensitizing properties. Naphthylene 1,5-diisocyanate is mainly used for the production of elastomers. 

This limitation is overcome when the elastomer is cast from a mixture consisting of a linear polyester or poly ether, diisocyanate and glycol or diamine. In this process, the hydroxy-terminated polymer (e.g., poly(ethylene adipate) or poly(oxytetramethylene) glycol) is treated with an excess of diisocyanate (e.g., naphthylene 1,5-diisocyanate, tolylene diisocyanate or diphenylmethane 4,4 -diisocyanate). The product is a pre-polymer which is, in effect, a mixture of isocyanate-terminated polymer and unreacted diisocyanate. The pre-polymer is then mixed with either a glycol (e.g., 1,4-butanediol or 1,6-hexanediol) or diamine (which is usually a deactivated amine such as 3,3 -dichloro4,4 -diamino-diphenylmethane (MOCA)). The mixture is poured into a heated mould where it quickly sets. After about 30 mins the casting is removed from the mould and cured at about 110°C for 24 hours. 

Isocyanic acid, 1,5-naphthylene ester. See 1,5-Naphthalene diisocyanate Isocyanic acid, m-phenylenedimethylene ester. See m-Xylylene diisocyanate Isocyanic acid, phenyl ester. See Phenyl isocyanate... 

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