Study On The Processes Of TGIC And TMGIC

Thermosetting powder coating is widely used in all areas of life due to its lowVOC, high efficiency and excellent coating process characteristics.1,3,5-triglycidylisocyanurate （TGIC） and tris （2,3-epoxy-2-methylpropyl） isocyanurate（TMGIC） arecuring agent of thermosetting powder coating. High purity TGIC without chlorineresidue also has excellent electrical performance in conditions of high temperature,which can be used to make electrical insulating materials, printed circuit, laminate andplastic stabilizer. Because of its good weather resistance, high thermal stability andsuperior mechanical performance, its usage is very extensive. TMGIC, the alternativesand derivatives of TGIC, which is better than TGIC in mechanical properties, electricproperties, resistance to UV and weather resistance. As a very promising product, itsservice life is5⁶times longer than the epichlorohydrin resin.In order to synthesize high purity TGIC without chlorine residue and improve theyield of TMGIC, we studied the preparation of TGIC via epoxidation of TAIC usinghydrogen peroxide as green and pollution-free oxidant. On the other hand, we alsostudied the preparation of TMGIC adopting recycled4A molecular sieve as thedehydrant. These new and green technics for preparation of TGIC and TMGIC wasstudied in three reaction systems.1) Preparation of TGIC from TAIC using H₂O₂-nitrile system:We used30%H₂O₂as oxidant and nitrile as a carrier of the peroxide. The best epoxidation condition ofpreparing high purity TGIC without chlorine residue is:n（H₂O₂）: n（TAIC）: n（PhCN）=5:1:3,50℃,8h, methanol as solvent. Under these reaction conditions, the yield ofTGIC was82.0%.2) Preparation of TGIC using H₂O₂-phosphotungstic acid system: The epoxidationwas carried out by phase transfer catalytic and quaternary ammonium salts ofheteropolyacids as catalysts. The key factors influencing the epoxidation were alsostudied, such as the amount of catalysts, concentration of hydrogen peroxide, reactiontemperature, reaction time and reaction solvent. On the basis of single factor test,orthogonal experiment was carried out to obtain the optimal reaction conditions, whichare detailed as: ethylene dichloride as solvet, n（H₂O₂）: n（TAIC）: n（PWA）=200:20:1,55℃, and18h, Under these conditions, the conversion rate of TAIC was98.4%andthe selectivity of TGIC was87.0%. 3) Preparation of TMGIC via2steps: The reaction was tried to use recycled4Amolecular sieve dehydrant instead of azeotropic distillation in the condition of lowpressure. The key factors influencing the reaction were studied, such as the mole rationbetween cyanuric acid（CA） and methyl epichlorohydrin（MECH）, amount of catalysts,reaction time in the first and second step, and reaction temperature. Simplexoptimization is used to obtain the best synthesis conditions:0.57g TBAB, cyanuricacid: MECH=1:21,97¹10℃（first step）,36℃（second step）, and7h.Under theseconditions,the yield of TMGIC was87.1%and the purity of TMGIC was98.3%.