1, Promote plasticization
2, Reduces torque/friction
3, Improve the wetting effect of pigment filler and glass fiber
4, Reduces viscosity
5, Slip/anti-stick effect
6, Inside and outside can be lubricated
The chemical reaction of epoxy resin and dicarboxylic acid dihydrazide:
It can be seen from the above reaction that the main reaction is the addition reaction between the epoxy group in the epoxy resin and the active hydrogen in the amine or amido group to form a hydroxyl group. The reaction between the hydroxyl group and the hydroxyl group can also generate secondary bonds and water, which increases the crosslinking density of the resulting polymer, that is, the film-forming product, and becomes a coating film with good performance.
The chemical reaction of epoxy resin and phenolic hydroxyl resin:
It can be seen from the above reaction that the hydroxyl group in the epoxy resin reacts with the anhydride of benzophenone tetracarboxylic dianhydride to form a carboxyl compound, and then the carboxyl group of this carboxyl compound reacts with the epoxy group in the epoxy resin to form an ester. pe wax flakes And finally a coating film of polymer compound is formed.
Three, epoxy resin
Epoxy resin is the most important component in epoxy powder coatings, and it is also the component that accounts for the largest proportion of mass in the composition of powder coatings. The end groups of epoxy resins have reactive epoxy groups (or glycidyl groups) and hydroxyl groups on the side groups. The reactivity of the groups varies with the molecular weight of the resin and the structural surface of the resin. There are many types of epoxy resins and they are widely used. However, epoxy resins for powder coatings should have the following characteristics.
(1) The molecular weight of the resin is small, but the glass transition temperature is higher than 50°C, the resin is brittle, it is easy to be mechanically crushed to obtain the required particle size at room temperature, and the formulated powder coating is not easy to agglomerate at room temperature.
(2) The resin has a low melt viscosity at the curing temperature of the powder coating, and it is easy to level to obtain a relatively thin and smooth coating film.
(3) The compatibility between different specifications of resins is good. By mixing resins with different softening points, viscosities and epoxy values, the resins with the required technical indicators can be adjusted, and the powder coatings can be made into different requirements.
(4) The resin has good dispersibility for pigments and fillers, and has good powder blending properties for different curing agents (or cross-linked resins), and can be used to formulate powder coatings with different performance requirements.
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