What are the main components of epoxy adhesive?

Epoxy adhesive is made of polyurethane prepolymer modified epoxy resin (component A) and self-made curing agent (component B) in a ratio of 10:1 to 1:1 (weight ratio) to make it resistant to high temperature and toughness. , Reactive curing system. Wherein the hydroxy terminated polyurethane prepolymer is a polysiloxane diisocyanate and a certain proportion of the isocyanate groups is made under certain conditions of the reaction-terminated polysiloxane polyurethane prepolymer, the polyurethane prepolymer and then using this epoxy resin Perform modification treatment. The self-made curing agent consists of diamines, imidazole compounds, silane coupling agents, inorganic fillers and catalysts.

1, epoxy resin matrix

Both molecular chain having an epoxy group, with active hydrogen-containing amine compound and an acid anhydride to form a dense three-dimensional network structure of cross-linking reaction, so that the cured resin is a thermoset (non-melting heat; difficult to dissolve with a solvent ).

2, curing agent (crosslinker)

Common curing agents organic amines and anhydrides curing agent. Amine curing agents generally can be cured at room temperature or low temperature, anhydride, aromatic curing agents often require heat curing. Anhydride and aromatic cured epoxy adhesives have higher heat resistance and strength, and amine curing agents are more toxic than anhydrides.

3, additives 4, fillers such as barium sulfate, epoxy resin

Bisphenol A epoxy resin is the most commonly used epoxy resin, accounting for about 75%-80% of the world's total epoxy resin. The R group of the bisphenol A epoxy resin contains two benzene rings. The epoxy group and the hydroxyl group are reactive and crosslink with the curing agent to form a dense three-dimensional network structure, so that the cured resin has good mechanical strength, good chemical resistance, excellent dimensional stability and low expansion rate; ether bond The hydroxyl group is a polar group, which helps to improve the wettability and adhesion; the ether bond and CC bond make the macromolecule have a certain flexibility; the benzene ring gives the polymer heat resistance and rigidity.