Preparation And Characterization Of Room Temperature Curing One-component Construction Structural Epoxy Adhesive

Due to their good adhesion strength, various adhesive objects, small volume shrinkage, high aging resistant and excellent chemical reagents resistant, epoxy adhesives have been widely used in the construction field. At present, most of the construction structural epoxy adhesives are of two-component packaging type. In comparison with two-component adhesives, one-component type shows many advantages. In the production process, a stoichiometric mixture of epoxy resin, latent curing agent, fillers and other additives are packing in one container. It can avoid the waste of time, material loss, measurement error and negative influence on the performance of the adhesive during two-component mixing process, which is beneficial to automate production. Therefore, one-component construction structural epoxy adhesive has promising applications. In this thesis, a preparation of novel room temperature curing one-component epoxy structural adhesive was achieved.Firstly, the moisture-induced latent ketimine curing agent for epoxy resin was successfully synthesized by1,3-bis(aminomethyl) cyclohexane(1,3-BAC) and methyl i-butyl ketone(MIBK), and the effects of reaction conditions on the conversion rate of ketimine were investigated. Results indicate that a water rate of97.5%for the reaction was achieved using a molar ratio of amine to ketone1:3at an oil bath temperature of170℃for3hours and the structure of the synthesized ketimine was confirmed by the infrared spectrum. Gas chromatograph and mass spectrogram showed that1,3-BAC’s purity was70.689%.The conversion rate of1,3-BAC and MIBK was about100%, after the calibration of1,3-BAC’s purity.Then, an optimum formulation of room temperature curing construction structural epoxy adhesive was obtained by optimizing the type and quantity of epoxy resin, ketimine, fillers, coupling agent and accelerating agent. The tensile strength, compressive strength and bending strength of this novel epoxy adhesive was20.62MPa,40.04MPa,71.09MPa respectively after conservation at25℃for14days. This homemade adhesive can reach the same mechanical strength of one-component adhesiveアドガ-ドPC-1but cured under the more rigorous condition, which reveals that the curability of homemade adhesive was better than that ofアドガ-ドPC-1. Lastly, the shelf-life stability of a stoichiometric mixture of the epoxy resin and ketimine was studied by fourier transform infrared spectroscopy. The epoxide’s reaction conversions were calculated from the changes in the magnitude of the absorption peak at910cm-1(epoxy group), with the peak at1580cm-1(benzene ring) used as an internal standard. Results indicate that, the epoxide’s reaction conversion was just8.20%after30days in the environment of RH10%. Its shelf life is better than that of the one-component system of the same raw materials tested by Yokohama Rubber Company. Therefore, the comprehensive performance of shelf-life stability and curability of homemade one-component adhesive is better than that ofアドガ-ドPC-1which is the world’s only commercial product of room temperature curing one-component epoxy structural adhesive.