Room temperature curing agent for general epoxy resin

Since the 1990s, many progress has been made in the research of heat resistance and room temperature curing of epoxy adhesive For example, Russian scientific research institutions have made achievements in the research of using special silicone resin and bismaleimide modified epoxy resin to raise the maximum working temperature of the adhesive to more than 400 ℃ In recent years, various kinds of room temperature curing structural adhesives have been reported one after another There are nearly 2000 kinds of two-component room temperature curing adhesives introduced to the world in 1993 by only one American commercial journal However, there are few researches on epoxy adhesive which can cure at room temperature and heat resistance at the same time Experts recently focused on one of the common type - bisphenol A epoxy resin as the substrate of room temperature curing adhesive Bisphenol a type epoxy resin is one of the most widely used and the largest production in the epoxy resin family The research on its heat resistance and room temperature curing technology is also the most mature Many products in this field have been put on the market and achieved good economic benefits According to experts, for example, domestic DG-2 and dg-3 room temperature curable heat-resistant adhesives, bisphenol-A epoxy resin and liquid carboxyl terminated NBR are used for pre reaction, modified amines and imidazole curing agents are used, and appropriate organosiloxane additives are added After 7 days of room temperature curing, the highest strength and service temperature can be achieved The peel strength of T-type can be 30-60n / cm, and aluminum and aluminum alloy can be bonded Copper, brass, stainless steel, carbon steel, nylon and other materials Another domestic CY-22 adhesive is made up of epoxy 618 (E-51) resin, modified amine curing agent and heat-resistant filler It can be put into use after curing at room temperature for 24 hours The shear strength at 25 ℃ is 14.0mpa, and it can also maintain a certain strength at 120-150 ℃ In addition, the adhesive has good compression and wear resistance, which can be used not only as heat-resistant structural adhesive, but also as wear-resistant repair agent and coating Domestic researchers also developed j-200-1d room temperature curing adhesive E-5l epoxy resin was modified by isocyanate terminated polyurethane prepolymer, and composite curing agent with modified aromatic amine structure was self-made The adhesive strength of the product is high, and it also has excellent moisture and heat aging resistance Although the research of room temperature curing heat-resistant epoxy adhesive has made some progress, there are still some problems, such as the poor high temperature resistance compared with the heat curing heat-resistant epoxy adhesive, which is mainly manifested in the lower shear strength and peel strength at high temperature, and the lower maximum use temperature Experts said that in the future, the research focus should be on further improving the temperature resistance of epoxy resin The specific methods include modifying epoxy resin with high temperature resistant resin, synthesizing new heat-resistant epoxy resin, etc.; at the same time, synthesizing new heat-resistant curing agent that can be cured at room temperature, or developing a room temperature curing system with better heat-resistant performance through modification and compounding, and preparing a suitable room temperature curing system In addition, the relationship between the microstructure, structure and high temperature properties of epoxy resin and the relationship between its viscoelastic behavior and toughening mechanism should be further explored.