| Free TDI come from TDI- TMP crosslinkers is an important kind of room pollutions. Free TDI is studied in this paper and the content is decreased to below 0.5% by using metal ion catalyst-polymerization method.Low TDI content TDI-TMP crosslinkers are synthesized from metal ion compound/n-butyl alcohol catalyst systerm. The best catalyster is selected by orthogonal experiments. Catalyster consumption, react temperature, antioxygen, anti-xanthochromia agent are discussed which have great influence on products'characters. GC-MS is used to determine content of free TDI, reaction kinetics is analysed by chlorhydric acid/n-dibutyl amine titration -NCO method and DSC, so the system activation energy is calculated. The TDI-TMP crosslinkers and hydroxyl resin are finally used to produce coatings and the films of which are determined ether.The results show that A101/n-butyl alcohol catalyst systerm has the best effect. Excellent low free TDI content (below 0.5%) TDI-TMP crosslinkers can be produced when the catalyster content is 1.0%, reaction temperature is 70℃, assistant content is 2.16%, -NCO:OH mol ratio is 2:1. The analysis of reaction kinetics results show that the reaction is second-order when the temperature is from 70℃to 80℃. The activation energy is 71.11kJ·mol-1 in non catalyster system but which in A101 catalyster system is 58.74kJ·mol-1. Metal compound A101 decreases activation energy of TDI-TMP polymerization system obviously. The catalyst mechanism of A101 to TDI-TMP system is that metal ions, TDI and alcohol form a ernary complex compound, so the reactions become easy.PU coatings is made by TDI-TMP crosslinkers. The film is clear and the luster is uniform. The films are well after being immersed into 3% NaCl solution, 10% H2SO4 solution and 10% NaOH solution for 120h. Free TDI content of crosslinkers is below 0.5%, so the crosslinkers are environment friendly and have a bright market.
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