What is the function of paint curing agent? Coatings curing agents can be divided into room temperature curing agents and heating curing agents according to their uses. As mentioned above, epoxy resin has excellent general properties when cured at high temperature, but the coatings and adhesives used in civil buildings need to be cured at room temperature due to the difficulty of heating, so most of them use aliphatic amines, aliphatic rings and polyamides, especially coatings and adhesives used in winter. It must be combined with polyisocyanates or use polyaromatic alcohols with a foul odor.
Medium temperature curing agent and high temperature curing agent should be based on the heat resistance of implant and the heat resistance, adhesion and resistance of curing material. Choices are concentrated in polyamines and anhydrides. Because of its excellent electrical properties, acid anhydride curing products have been widely used in electronic and electrical fields. Aliphatic polyamines have excellent adhesion, alkali resistance and water resistance. Aromatic polyamines are also very resistant. Because the nitrogen element of amino group forms hydrogen bond with metal, it has good antirust effect. The higher the concentration of amine, the better the anti-rust effect. The ester bond between anhydride curing agent and epoxy resin has high resistance to organic acid and inorganic acid, and its electrical properties are generally superior to those of polyamines.
What is the concept of mid-temperature curing agent: the curing temperature of mid-temperature curing agent is 50-100 C, and the curing temperature of high-temperature curing agent is more than 100 C. There are several curing agents belonging to low-temperature curing type, such as polyisocyanate type and polyaromatic alcohol type. T-31 modified amine and YH-82 modified amine developed and produced in China can be cured below 0 ~C. Room temperature curing includes aliphatic polyamine, alicyclic polyamine, low molecular weight polyamide and modified aromatic amine.
Some alicyclic polyamines, tertiary amines, orbital azo and boron trifluoride complexes belong to the intermediate temperature curing type. Aromatic polyamines, anhydrides, phenolic resins, amino resins, dicyandiamide and hydrazine are high temperature curing agents. For high temperature curing systems, curing temperature is usually divided into two stages, namely, low temperature curing before gelation. After reaching the gel state or slightly above the gel state, the curing temperature (solidified) solidified at high temperature and solidified as pre curing (pre curing) relative to the previous stage.