Waterborne epoxy resin coating modification principle of crosslinking agent

Waterborne epoxy resin coating modification principle of crosslinking agent,To make between epoxy resin and crosslinking agent can fully miscibility, the crosslinking. We have to make the solubility parameters of the match.

Solubility parameters of crosslinking agent and solubility parameter differences between hydrophobic epoxy resin, the film comprehensive performance is bad; And solubility parameters of small crosslinking agent, and the solubility parameters of the epoxy resin match, if can get comprehensive performance crosslinking can better coating, but it is difficult to dissolve in water, not stable dispersion in water, need to adopt some methods such as salt to improve its hydrophilicity can make its stable dispersed in water.

Waterborne epoxy crosslinking agent presently used mainly for the modified amine crosslinking agent, it is divided into three categories: a. amide amine, mainly using C18 fatty acid and amine condensation products; Biggest more than 36 dimer acid and ethylene polyamine condensation products; C. amine adduct, mainly amine and epoxy adduct.

Waterborne epoxy crosslinking agent commonly used amine mainly aliphatic polyamine, m-phenylene diamine, mann nicky alkali, polyoxyethylene diamine, etc. But in this three kinds of crosslinking agent and epoxy resin compatibility is poor, lead to applicable period short and poor resistance to water, should be modified to improve its compatibility with epoxy resin. The modification methods of the most commonly used is to reduce the content of primary amine.

This method has a dual role: a. reduces the overall reactivity of crosslinking agent, extend the applicable period; B. to improve its compatibility with epoxy resin. The typical method is to use single epoxy compounds or acrylonitrile. Although this approach reduces the content of primary amine, secondary amine on the skeleton still produce enough crosslinking; Another way is by vacuum distillation to remove unreacted free amine.

Remove the cause of free amine is when two components mixture, low relative molecular mass of amine can exist in the water phase, the free amine can increase the water sensitivity of coating.

Above although modification methods to improve the compatibility, but crosslinker water-soluble also decreases, as the crosslinking agent stable dispersion in water, need to add organic acids to improve its solubility in water, to keep the emulsion stability. But residual organic acid can reduce the water resistance and corrosion resistance of coating on the metal used to flash rust easily, so the use of organic acid should be as little as possible. A small amount of acid volatile after crosslinking, will not seriously affect the coating corrosion resistance.




Chinese name: Diethyl toluene diamine(DETDA)

Diethyltoluenediamine Raw material ：

TDA industrial, Sichuan production

Ethylene (Et) polymer grade, Shanghai production

TEA industrial imports

A reagent grade additives


Waterborne epoxy resin is refers to the epoxy resin in the form of particles or droplets dispersed in continuous phase dispersion in water medium and worthy of the stability of the dispersion system. Because epoxy resin is linear structure of thermosetting resins, waterborne epoxy curing agent must be added before the construction, issued by crosslinking biochemistry reaction at room temperature environment, the cured epoxy resin was changed the nature of the soluble fusible into insoluble by not melt spatial reticulated structure, shows excellent performance. Waterborne epoxy resin coatings not only has the many advantages of solvent epoxy coatings:

It is adaptable, to many substrate has a very high adhesion, after curing coating corrosion resistance and chemical resistance is excellent, and coating closed reduction, high hardness, good wear resistance and electrical insulation performance, etc.;

2 it is environmental protection performance is good, also has does not contain organic solvent or volatile organic compounds content is low, does not cause air pollution, and thus meet the requirements of the current environmental protection;

Three is a real water, in the water as disperse medium, the price is low, no smell, non-combustible, storage, transportation and also greatly improve the security in the use process;

Four is operational, construction of waterborne epoxy resin coatings operating performance is good, construction tool can directly with water washing, can be solidified at room temperature and damp environment, reasonable, curing time, and to ensure a high degree of crosslinking density.

This is usually the water-borne acrylic coatings and water-borne polyurethane coatings are incomparable. Waterborne epoxy resin with its outstanding performance advantages, make preparation of waterborne epoxy resin coatings is also has excellent performance, thus more and more important status in water product family, experts think the waterborne epoxy resin in the environmental protection today, prospect is very broad.

Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd 

Diethyl toluene diamine(DETDA)  http://www.yaruichem.com