Preparation And Properties Of Solvent-free Two-component Epoxy Terminated Polyurethane Adhesive

Compared with solvent polyurethane adhesive,solvent-free two-component polyurethane adhesive has little harm to the environment and human body,so it has developed rapidly.Epoxy resin adhesive has many advantages.So combining the two can get an adhesive with better performance.In this thesis,a solvent-free two-component epoxy terminated polyurethane adhesive was prepared with polypropylene glycol,liquefied MDI and epoxy resin E-51 as the main raw materials.At the same time,its comprehensive properties were discussed.The results showed that the prepared adhesive had excellent properties,with Shore D hardness of 78HD,impact strength of 26.08 Kj/m~2and shear strength of 20.94 MPa.The effects of NCO content and the amount of active diluent on the preparation of PU/EP adhesive were investigated respectively.It was found that the best reaction time for the preparation of polyurethane prepolymer was 3h,and the active diluent 660A significantly reduced the viscosity of PU/EP adhesive.The A component of epoxy terminated polyurethane adhesive was characterized by infrared spectroscopy.T31 curing agent and low molecular polyamide 650 curing agent are selected and compounded on this basis,and their addition amount and compounding proportion are determined respectively.Then T31,polyamide 650 and compound curing agent are used as component B of the adhesive.The effects of different amounts of active diluent 660A and accelerator DMP-30 on the mechanical properties and thermal stability of PU/EP adhesive were investigated.The results show that the comprehensive performance of PU/EP adhesive is the best when the addition of polyamide 650 is 25%,T31 is 12%,active diluent is 15%and accelerator is 2%.Shore D hardness reaches 66HD,tensile strength reaches 23.93MPa,elongation at break reaches 23.85%,impact strength reaches17.07 Kj/m~2,tensile shear strength reaches 11.31MPa,and surface drying time is 3.5h.PU/EP adhesive obtained by DSC has good component compatibility,and its glass transition temperature is lower than that of EP adhesive.The heat resistance of PU/EP adhesive obtained by TG and DTG is better than that of EP adhesive.KH-550 was used to modify nano-Si O₂,which was used as filler to fill PU/EP adhesive.The effects of dispersion time on the mechanical properties of PU/EP adhesive and the effects of different amounts of nano-Si O₂on the comprehensive mechanical properties,heat resistance,water resistance and surface appearance of PU/EP adhesive were studied.The results show that the filling effect is the best when the dispersion time is 20min and the addition amount of nano-Si O₂is 3%.Shore D hardness reaches 78HD,impact strength reaches 26.08Kj/m~2and shear strength reaches 20.94MPa.Through the analysis of contact angle and water absorption,it is concluded that when the amount of nano-Si O₂is 3%,the contact angle is about 77.3°,and the water absorption is about0.828%.Compared with that without nano-Si O₂,its water resistance is improved.Through the micro morphology analysis,DSC analysis and TG analysis of PU/EP adhesive,it is proved that nano-Si O₂can effectively improve the mechanical properties and heat resistance of PU/EP adhesive.