Let's understand the nature of epoxy in epoxy tubes

Editor:浙江和泰新材料股份有限公司 │ Time:2019-11-19 

The epoxy tube is made of electrical alkali-free glass fiber cloth impregnated with epoxy resin and processed by hot pressing in a baking and molding mold. The cross section is a round rod. The glass rod has high mechanical properties. Dielectric properties and good machinability. It is suitable for use as insulation structural parts in electrical equipment, and can be used in humid environment and transformer oil.

Let us understand the nature of epoxy in epoxy tube

No matter what form of water-based epoxy resin and water-based epoxy curing agent is selected, the water-based epoxy system that has practical application value is a dispersed multi-phase structure. It consists of water-based epoxy resin, water-based epoxy curing agent, and water. Phase composition, its film-forming mechanism is different from that of ordinary polymer emulsions such as acrylic emulsions (condensation and film formation, physical process), and is not exactly the same as the film-forming of solvent-based epoxy. In solvent-based epoxy systems, Both epoxy resin and curing agent are dissolved in organic solvents in the form of molecules, and the system formed is homogeneous. The curing reaction proceeds between molecules, so the curing reaction proceeds relatively completely, and the cured product formed is also homogeneous. .

Waterborne epoxy is a multi-phase system. Epoxy resin and curing agent are dispersed in the water phase as a dispersed phase. The cross-linking and curing process is a process of internal diffusion and cross-linking between particles during the evaporation of water. The degree of epoxy curing depends on four factors:

a) Compatibility: The better the compatibility between the water-based epoxy resin and the water-based epoxy curing agent, the more favorable the internal diffusion of the curing agent particles and the epoxy resin particles, and the better the curing reaction;

b) Particle size: When the particle size is small, the particles of the dispersed phase of the water-based epoxy resin and the water-based epoxy curing agent can sufficiently penetrate into the core to achieve a more complete degree of curing;

c) Hydrophilic-lipophilic balance value: The hydrophilic-lipophilic balance values of water-based epoxy resin and water-based epoxy curing agent are close to each other, and a consistent coexisting and stable state is achieved in the water phase. If the difference is large, the hydrophilicity is stronger. The components will gradually accumulate in the aqueous phase, causing the resin phase and the curing agent phase to separate;

d) Dispersion uniformity: In the state of multi-phase separation, the resin phase and curing agent phase can be evenly distributed in the water phase only through a certain mechanical stirring effect; (Epoxy is very important to stir and mix in the application) Some friends think that in the process of using oily epoxy, it can form a film with simple stirring or even without stirring. In fact, there is a big misunderstanding, because the oily epoxy used is dissolved by solid epoxy such as 75% of E- 20, even if no curing agent is added, the solvent can form a very hard dry film after the solvent is volatilized, but this dry film is cured without cross-linking of the curing agent, and becomes liquid after heating, and the dry film has no performance at all.