Study On Polyurethane Modified Epoxy Resin Adhesive

In this paper,a method of polyurethane modified epoxy resin adhesive which can meet the bonding of automobile body is put forward in view of the domestic and foreign research present situation of automotive adhesives,such as the requirement of high strength,environmental protection and safety.The use of imidazole curing agent,which can be terminated with the role of polyurethane,but also to re-release imidazole and epoxy resin from the curing reaction,is to achieve the polyurethane epoxy resin modification.The first step: the isocyanate group and polypropylene glycol(PPG-1000)reaction to obtain double-terminated isocyanate-based polyurethane prepolymer,through the isocyanate content of the test and the infrared spectrum of the characteristic peaks of the hydroxyl.The observation can determine the reaction completion time.The second step: imidazole-terminated double-terminated isocyanate-based polyurethane prepolymer,through the isocyanate content of the test and the infrared spectrum of isocyanate root changes,can determine the reaction time.The third step: modified polyurethane prepolymer and bisphenol A epoxy resin reaction,through the isocyanate content and infrared spectrum can be obtained reaction time.The polyurethanes modified epoxy resin prepolymer was used to study the contents of curing agent,curing temperature,diluent and filler to determine the content of curing agent.The experimental results showed that the ratio of polyurethane prepolymer to curing agent was 100: 20,the content of reactive diluent was 5%,the content of coupling agent was 0.5%,the content of nano filler silica was 0.5%,the polyurethane modified epoxy resin adhesive shear strength reached the maximum value of 20.3MPa,the elongation was at break 14.21%.