| TDI-TMP and TDI trimer are the main two kinds of TDI curing agents,and also they are the most widely used TDI curing agentat the present stage.Limited by the level of production technology,higher free monomer content is the main problems of domestic type TDI curing agent,high free monomer is not only a waste of resources,also can produce negative influence the performance of paint film,and the construction personnel's health and the environment is extremely harmful,therefore national restrictions also more and more severe,developing the appropriate TDI curing agent synthetic process conditions,it is imperative to meet the requirements of free TDI content.Based on TDI and TMP as the main raw material,synthetic TDI-TMP curing agent and TDI trimercuring agent,carry out the researchconte of free TDI less than 0.5%in polyurethane curing agent.By adopting different ways of feeding,solvent,reaction temperature,reaction time and heating temperature to study different conditions,determine the appropriate parameters of curing agent for polyurethane prepolymer synthesis reaction.At the same time based on TDI-TMP curing agent and TDI trimer of research on the effects of reaction conditions on the properties of the product,determine the TDI curing agent synthetic formula.Using synthetic curing agent with paint experiments,verify that the coating properties of curing agent.The results show that the reaction rate,free content in two aspects to consider TDI-TMP curing agent synthesis reaction,60 ? for more appropriate reaction temperature,catalyst amount of 0.11%,TDI/TMP ratio 3.85 suitable quality.Test in TDI trimer curing agent suitable synthetic technology conditions as follows:with DMP-30 as catalyst,the highest reaction temperature 60 ?,ethyl acetate and toluene mixed solvent,first added 60% solvent and reaction about 8 h. |
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