Epoxy resins are linear macromolecules that are thermoplastic and cannot be used alone, but their molecular structure contains active epoxy groups, hydroxyl groups, ether bonds, etc., which can be changed by crosslinking and curing reactions with various types of curing agents. For body structure. The curing of epoxy resins is mainly achieved by addition polymerization of curing agents and catalyzed ring-opening polymerization of epoxy groups. The epoxy resin and curing agent undergo a curing reaction at room temperature or high temperature to form a three-way network polymer. This network polymer has excellent bonding properties, anti-corrosion properties, mechanical properties, electrical properties, and chemical resistance properties.
There are many types of epoxy resins, but E-type epoxy resins are more commonly used, and there are multifunctional epoxy resins that meet special requirements and have better heat resistance than general bisphenol A-type epoxy resins. There are many types of curing agents for epoxy resins, but most of them are amines, modified amines and anhydrides. From the curing temperature, they are divided into low temperature, normal temperature, medium temperature, and high temperature curing. They are cured in various curing agents. The temperature and heat resistance are very different. Generally, a curing agent with a high curing temperature can obtain a cured product with excellent heat resistance. The epoxy resin cured at low temperature or normal temperature has limited heat resistance, but the high curing temperature limits it in many fields. usage of.
Bengbu Tianyu High-temperature Resin Material Co., Ltd. developed and produced a modified phenolic epoxy resin high-temperature curing agent, trade names are F-52B and F-51A, etc., and E-44 or E-51 epoxy resin according to 1 The weight ratio of 1: is formulated into glue to bond 45# steel test pieces. After curing at a high temperature of 180°C, the test pieces are placed in a muffle furnace and calcined at 800°C for one hour. After testing, there is still a shear strength of more than 1Mpa. After mixing with E-51 and F series curing agents according to the weight ratio of 1:1, the steel test piece and the aluminum test piece are respectively bonded, and the curing condition is 120°C/2h+150°C/2h+180°C/3h, at room temperature The shear strength of aluminum-aluminum is 10.09Mpa, the steel-steel is 12.16 Mpa, the test piece is tested at 250℃ for one hour, the aluminum-aluminum shear strength is 9.7 Mpa, the steel-steel is 15 Mpa, after 350℃ The strength of aluminum-aluminum is still 6.7 Mpa for half an hour.
This new type of curing agent can cure epoxy at high temperature and can be added to the accelerator at intermediate temperature to cure. It can be cured at 120℃ for two hours when blended with multifunctional epoxy. There are powder and liquid for users to choose, so as to meet the needs of high-temperature adhesives, coatings, fiber-reinforced composite materials, diamond wheels, electric carbon materials and other industries.