Preparation And Application Of Non-toxic Low-viscosity TDI Trimer Curing Agent For Bright Wood Paint

Toluene diisocyanate(TDI)trimer curing agent can be added as an isocyanate component It can be used in a two-component polyurethane coating with the main paint component.After addition,it can improve the drying rate of the paint film and improve the hardness and wear resistance of the paint film Properties such as nature.At present,the TDI trimer products produced by domestic manufacturers generally have the characteristics of high free monomer content and poor compatibility.However,most of the TDI curing agents currently available on the market are imported or repackaged products,which are more costly than chemical synthesis method has increased significantly.Therefore,this article aims to research and develop the product of TDI trimer curing agent that can meet the market standards,and to study the application of construction.The specific work is as followsFirst,by comparing the indicators of the curing agent products obtained by selecting different catalysts,the most suitable catalyst is selected.The results show that when the tertiary amine catalyst synthesized by the Mannich method is used in the trimerization reaction,the synthesized product index is optimal.Under the same conditions,when the NCO conversion rate reaches 65%,the product TDI free value can reach 2.01%,and the viscosity Reached 325cpSecond,on the basis of using the catalyst,the synthesis conditions of TDI trimer were investigated.The results show that:by controlling the conditions for slowing down the rate of trimerization reaction,and increasing the solid content of the system during the reaction,it is beneficial to obtain products with lower TDI free value and viscosity,while appropriately lowering the temperature,reducing the catalyst input,and increasing the catalyst input The number of times is conducive to controlling and slowing the rate of trimerization reaction,and increasing the solid content of the reaction system is helpful to improve the utilization rate of TDI monomer during the synthesis process and promote the formation of oligomersThird,after mastering the law of reaction conditions,further optimize the synthesis process The results show that the optimized process is modified with 5%octadecyl alcohol,the reaction temperature is controlled at 50℃,the single addition of catalyst is 0.06%,the solid content of the stage is decreased by 8%,and the interval between each stage is 75min.Supplemented in 4 stages,its dosage accounts for 30%of the total TDI.The NCO value of the obtained product was 7.48%,the viscosity was 235cp,the tolerance was 3.57,and the TDI free value was 0.35%Fourth,compare the construction application of the curing agent synthesized under the best conditions with the commercially available curing agent.The results show that the self-synthesis curing agent can reach the market standard in product index,storage stability and paint film performance,and the product has certain competitiveness.