应用于聚氨酯树脂的有机多元异氰酸酯，按-NCO基团的数目可分为二元异氰酸酯、三元异氰酸酯及聚合型异氰酸酯三大类。其中最重要的是甲苯二异氰酸酯，共有3种规格：

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com.cn kongzhiqi.37ix.com.cnOrganic polyisocyanates used in polyurethane resins can be classified into dibasic isocyanates, ternary isocyanates and polymeric isocyanates according to the number of NCO groups. The most important of these is toluene diisocyanate, which has three specifications:

TDI一100：含100%的2，4一甲苯二异氰酸酯。
TDI-100: Contains 100% 2,4-toluene diisocyanate.
TDI一80：含80%的2，4一甲苯二异氰酸酯，20%的2，6一甲苯二异氰酸酯。
TDI-80: contains 80% 2,4-toluene diisocyanate and 20% 2,6-toluene diisocyanate.
TDI一65：含65%的2，4一甲苯二异氰酸酯，35%的2，6一甲苯二异氰酸酯。
TDI-65: Contains 65% 2,4-toluene diisocyanate and 35% 2,6-toluene diisocyanate.
这3种规格的TDI是由于原料甲苯二胺的制法不同分别制得的。
The three specifications of TDI were prepared by different methods of preparing toluene diamine.