Water-based epoxy anticorrosive coatings mainly include the following two types:

①、Type I, self-emulsifying type: The most significant feature is that the low molecular weight epoxy resin and curing agent used are not in an emulsion state.

This type of water-based epoxy anticorrosive coating consists of low molecular weight liquid epoxy resin (epoxy equivalent around 190) and a water-soluble epoxy curing agent. During use, this curing agent must function both as a cross-linking agent and an emulsifier. Such curing agents are based on polyamines, with surfactant segments introduced into their molecules, making them amphiphilic and thus highly emulsifying. This system generally does not require the addition of coalescing solvents, resulting in zero VOC.

Typical formulation composition of Type I water-based epoxy anticorrosive coating:

Characteristics of this type (mainly compared to Type II):

* Fully emulsifies during mixing and stirring of the two components, with certain requirements for mixing and shearing speed;

* Higher solid content, zero VOC emissions;

* Dries slowly due to complete reaction drying, especially at low temperatures (below 15°C);

* Very short pot life after mixing, generally about 15-30 minutes (at 25°C). Even with a large amount of glacial acetic acid added, it is difficult to exceed 2 hours (at 25°C), and adding glacial acetic acid may reduce the mechanical properties of the coating film. Using it beyond the pot life can easily lead to pinholes and loss of gloss (topcoat).

②、Type II, emulsion type: The most significant feature is the use of epoxy resin emulsion and water-based curing agent (emulsion or solution).

This type of water-based epoxy anticorrosive coating consists of an emulsion made from higher molecular weight water-based epoxy resin and a water-soluble amine curing agent or curing agent emulsion. The water-based epoxy curing agent (emulsion or transparent solution) has good compatibility with the epoxy resin emulsion and does not require emulsifying properties. Most of this type contain a small amount of organic solvent as a coalescing aid (generally not exceeding 10%). Since the coating film of water-based epoxy coatings is formed by the cross-linking reaction between epoxy resin and curing agent, resulting in a network structure, the coating film exhibits good corrosion resistance, chemical resistance, and mechanical properties.