PROCESS FOR PREPARING ε-CAPROLACTAM BLOCKED TOLUYLENEDIISOCYANATE Russian patent published in 1997 - IPC

FIELD: manufacture of tyres, industrial rubber products and other materials. SUBSTANCE: invention describes process for preparing e-caprolactam blocked toluylenediisocyanate (mixture of 2,4-and 2,6-isomers in 80:20 or 65-35 ratio). Its melt is granulated at temperature lower than dissociation temperature of the product into original substances. The process comprises carrying out reaction in melt of reagents in stoichiometric ratios at 150-160 C to achieve 1-2 wt.-% of free e-caprolactam in the product melt. It makes possible to reduce granulation temperature to 145 C, prevent dissociation of product and recycle toluylene diisocyanate to working zone. EFFECT: higher efficiency.