Study on the Application of ATBN Modified High Temperature Epoxy Adhesive (I)

Abstract : An epoxy resin adhesive toughened with amine-terminated nitrile rubber (ATBN) is introduced. The adhesive can be cured at room temperature and has good adhesion, dielectric and electrical insulation properties. -55 ~ 200 °C, to meet the needs of high temperature.

Keywords: epoxy resin; room temperature curing; heat-resistant adhesive

The development of China's aerospace industry requires matching room-temperature curing heat-resistant adhesives. The main domestic products in this area are the SY series of Beijing Aviation Material Research Institute, the DG series of Chenguang Chemical Institute, and the J series of Heilongjiang Provincial Petrochemical Institute. In this paper, a mixed epoxy resin is used as the main resin of the adhesive, an amine-terminated nitrile rubber (ATBN) is used to toughen the epoxy resin, and a polyamide curing agent and a tertiary amine accelerator are used to develop a room-temperature curing resistance. Thermal adhesive, its adhesive strength, medium resistance, heat resistance, electrical insulation properties are better and meet the technical requirements of a project.

1 Experimental section

1.1 Raw materials

Epoxy resin E 51, Wuxi; Epoxy resin AG 80, Shanghai; Polyamide curing agent 315, Shanghai; Toughener ATBN, imported; Accelerator S1, homemade; Titanium dioxide, Tianjin.
1.2 Preparation of Bonding Specimens

Normal temperature shear specimens were made of Ti6Al4V titanium alloy, and 200°C shear specimens were made of LY12CZ aluminum alloy. The surface of the specimens were all grit blasted. The curing conditions were 25°C×7d or 80°C×4h.

1.3 Performance Test

Shear strength, GB/T7124-1986; period of application, GB/T7123.1-2002; resistance to media, OCT180517-83; insulation, GB10064-88.

2 Results and Discussion

2.1 Study of adhesive formulation

In order to meet the requirements of room temperature curing and heat resistance of 200°C, high-functionality epoxy resin is mixed with bisphenol A epoxy resin to form a mixed epoxy resin as the main resin of the adhesive; the active functional group with terminal amine groups is selected. The acrylonitrile-butadiene rubber ATBN is toughened to ensure effective toughening of the adhesive while increasing the cross-linking density of the adhesive, thereby improving the heat resistance of the adhesive and balancing the conflict between the adhesive toughness and heat resistance; in order to ensure the adhesive Room temperature and low temperature performance and the reactivity of the adhesive, the polyamide curing agent with better toughness and reactivity is selected, and the self-produced tertiary amine accelerator is used to improve the reactivity of the adhesive system. Titanium dioxide is added as a filler. According to the above ideas for adhesive formulation design. Table 1 shows the shear strength of the adhesive after curing at 80°C for 4 h with different amounts of ATBN.

As can be seen from Table 1, the toughening agent ATBN mass fraction of 20 parts, its highest normal temperature shear strength, up to 37.2MPa, the amount of toughening agent is between 10 to 30 parts at 200 °C shear strength is basically the same, this article chooses ATBN dosage for Twenty trials were conducted as follows.

2.2 Effect of Different Curing Conditions on Bonding Shear Strength

The bond shear strength of the adhesive at room temperature and 200°C was tested after curing under different conditions. The results are shown in Table 2.

From Table 2, it can be seen that the adhesive has higher room temperature shear strength after curing at 80°C×4h than after being cured at 25°C×7d. This is a common feature of room-temperature curing epoxy adhesives, and the shear strength at 200°C is basically the same. This may be related to the continued curing reaction of the adhesive during testing at high temperatures.

(to be continued)