Synthesis And Characteristics Of The Silicon Modified Blocked Isocyanate

Polyurethane was a kind of materials that had unique structure and terrific properties between rubber and plastic,and because of those wonderful properties,the use of polyurethane had become very large.Waterborne polyurethane as a derivative of polyurethane with its good performance of environmental protection,safety,good mechanical properties and easy modification etc.Organic silicon material had many good properties that polyurethane did not have.For example,improve the thermal properties of polyurethane materialsIn this paper,use trimethoxy(methyl)silane and polyether glycol as raw material prepared Polyurethane pre polymer.Then,the water blocking isocyanate curing agent was synthesized by using ethylene glycol methyl ether and methyl ethyl ketone.At the same time using polyether glycol and Trimethylolpropane with TDI reaction,and use methyl ethyl ketone as blocked agent.Mixing blocked isocyanate curing agent and resin with a certain proportion of the preparation of the film,and the performance of the coating to do a certain research.Through the analysis of the dosage of modifier,the way of feeding,the temperature of the experiment,the closing time and so on,the best experiment plan was determined.There was a result in the experiment that dripping TDI to polyether polyols can make the reaction stability,and by controlling the temperature to investigate the optimum temperature and high temperature also easily lead to the response is too intense,low temperature reaction time is too long,finally determine the tenperature at 50? can speed up the reaction time,and can effectively prevent the reaction is too severe.At the same time,the experiment found that using ethylene glycol monomethyl ether and methyl ethyl ketone oxime closed together can more effectively blocked polyurethane pre polymer,due to hydroxyl compound closed isocyanate reactive low,although there are conducive to the storage of sealing products,but the closure of the use of a longer time,and oxime sealant for isocyanate have higher activity,so the use of methyl ethyl ketone oxime and ethylene glycol monomethyl ether closed together,can effectively reduce the blocking reaction time.