What are the categories of common epoxy structural adhesives?

Epoxy structural adhesive is solvent-free, liquid epoxy resin adhesive, can be cured at room temperature or temperature. After curing, the following layer is medium to hard, so it can withstand extremely strong shock and vibration, and the next layer has good mechanical properties, good electrical insulation, and can withstand temperature changes and flexural tearing stress. Non-corrosive, good adhesion to metal, ceramic, vulcanized rubber, glass fiber products, and carbon fiber products. Temperature and oil resistance，Classification of epoxy structural adhesives

According to the strength of the structural glue is divided into three levels, as follows:

The first stage is used for bonding the main stress structure, which is a structural adhesive;

The second stage is used for bonding of the secondary stress structure, quasi-structural adhesive;

The third level has no requirements for peel strength and should be a non-structural adhesive，There is no perfect standard for the definition and classification of structural adhesives in China. Usually, structural adhesives are divided into two categories of high strength, high toughness and medium strength and medium toughness according to the stress situation of the bonding object and the bonding strength: the shear strength of steel with the main stress structure is ≥25MPa, the tensile strength is ≥ 33MPa, and the uneven tearing strength is ≥40kN/m. The shear strength of the adhesive used in the secondary stress structure is 17 ~ 25Mpa, and the uneven tearing strength is 20 ~ 50kN/m.According to the curing temperature, epoxy structural adhesives can be divided into four categories: high temperature curing, medium temperature curing, room temperature curing and low temperature curing.

① The temperature, toughness and heat resistance of the high-temperature curing epoxy structural adhesive are high, and it is mostly used for bonding of the main stress structure;

(2) The medium temperature curing epoxy structural adhesive is mainly to meet the needs of the aircraft industry and the development of the adhesive, because aluminum alloy at 120℃ above the beginning of the grain boundary corrosion tendency, and with the increase of temperature and increase, the strength and toughness of the green alloy after grain boundary corrosion will decline, so the curing conditions of adhesive bonding aluminum alloy do not exceed 130℃/4h;，③ The application of room temperature curing epoxy structural adhesives is more extensive. The application in the field of civil construction is more important, and it is one of the main varieties of building structural adhesives;

④ Low temperature curing epoxy adhesive is a new kind of adhesive developed in recent years in order to meet the needs of low temperature construction in winter, which can be constructed and cured at 0℃ and even below -10℃. According to heat resistance, structural adhesives can also be divided into three categories: general type (≤80 ° C), high temperature resistance type (≥150 ° C) and medium temperature resistance type (between medium and the former).