Method for preparing high-strength epoxy resin adhesive

Abstract

The invention relates to a method for preparing cured modified epoxy resin. The method comprises the following steps: mixing prepolymers at different weight ratios and synthesizing at molar ratios of 2:1, 3:2 and 4:3 with epoxy resin in a container at room temperature, adding boron trifluoride ethylamine curing agent which is 3% of the weight of the mixed resin, stirring uniformly, mixing the mixture in the container for 1 hour in an ultrasonic cleaner; and putting the mixture in a vacuum baking oven to remove air bubbles for 2 hours. The polymerization activity of an epoxy group is greater than that of a spiral ring group, and the epoxy group can be subjected to the ring opening reaction at lower temperature. The starting temperature of curing reaction is 102 DEG C, and modified epoxy resin containing 20% of prepolymer is cured for 4 hours at the constant temperature of 102 DEG C and then cooled. The invention avoids the defects of the matrix, which are probably resulted from the aggregation of spiral ring monomers and ensures that the resin is more stable and practical.

Description

technical field [0001] The invention relates to a preparation method of an epoxy resin adhesive, in particular to a preparation method of a cured modified epoxy resin adhesive. Background technique [0002] At present, the adhesives produced in industry will shrink in volume during the curing process. For example, the volume shrinkage of epoxy resin is more than 5% [31] . To eliminate the internal stress caused by this factor, the formulation of the adhesive must be changed fundamentally, or the adhesive must be redesigned. The widely used epoxy resin will inevitably produce a certain residual stress due to volume shrinkage when it is cured. The residual stress in the resin is a potential destructive factor, which makes the interface between the resin and the fiber or the adhesive joint in the absence of external load. It is subjected to considerable stress, resulting in a decrease in strength, and even cracking of the composite material, dimensional instability or degumm...

AI Technical Summary

Problems solved by technology

The widely used epoxy resin will inevitably produce a certain residual stress due to volume shrinkage when it is cured. The residual stress in the resin is a potential destructive factor, which makes the interface between the resin and the fiber or the bonded joint unloaded. It is subjected to considerable stress, which leads to a decrease in strength, and even causes cracking of the composite material, dimensional instability or degumming of the glued joints, etc.

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