Hydroxyl alkyl amide class coating crosslinking agent

Hydroxyl alkyl amide class coating crosslinking agent,(Hydroxyl alkyl amide, HAA) TGIC is gradually substituted weathering powder coating the first major types of crosslinking agent, the main varieties have a Primid XL552 and Primid QM1260 two kinds.

The crosslinking of HAA principle is to use the beta on hydroxyl alkyl esterification with resin on the carboxyl to dehydration reaction. Due to the reaction process can form mouth oxazoline salt intermediates, thus esterification reaction activity is very high, do not need to join the catalyst.

From the toxicology Angle analysis, two kinds of HAA class crosslinking agent are completely safe. QM1260 XL552 relative molecular structure which is the only difference between the hydroxyl of carbon atoms on one more methyl groups, the existence of the steric hindrance effect may slightly reduce the activity of hydroxyl groups, but the crosslinking after the formation of ester groups can play a shielding effect, so as to improve its hydrolytic stability, inhibition film yellowing.

HAA as crosslinking agent is the chief drawback of preparation of powder coatings due to the release of water molecules crosslinking process, will affect the density of paint film. For the coating thickness may cause pinhole and foaming. To overcome these problems, we need to slow down the coating crosslinked speed, keep the coating under the condition of low melt viscosity for a long time, for the water molecules escape time.

Beta hydroxy alkyl amide is polyester powder coating is a new kind of high efficient non-toxic crosslinking agent. Beta hydroxy alkyl amide application in powder coating test, the results show that the alternative to the traditional TGIC crosslinking agent.

Because of TGIC toxicity and harm to the environment, since the 1990 s, many countries have banned or restricted in the world for its application. Appeared in the powder coatings industry and its many alternatives, in which performance is close to TGIC, affect the largest and the most widely application scope for hydroxyl alkyl amide (Primid XL552).

Objectively, TGIC and hydroxyl alkyl amide (T105), after all, are two different compounds, the reaction mechanism, reaction process is different, need to study the problem of hard to avoid can appear different in different solutions.




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


To promote the hydroxyl alkyl amide (T105) you have to research its differences with TGIC. TGIC is through its three epoxy group and carboxyl polyester carboxyl and realize the crosslinking reaction, its reactivity is relatively small, there is no by-product in the process of reaction. Although nitrogen molecules containing three atoms, but closed triazine ring, make it stability without the structure of oxidation. And it is oil soluble, has good compatibility with carboxyl polyester.

T105 through four hydroxyl and carboxyl polyester carboxyl and realize the crosslinking reaction, its reactivity is opposite bigger, reaction process with water. Contains two bare nitrogen atoms in molecules, making it more easily oxidized and lose stability. And it is water soluble, and carboxyl polyester completely incompatible, only scattered in the carboxyl polyester.

By contrast can be seen in the above, in addition to the T105 has bad compatibility with carboxyl polyester should strengthen outside mixing dispersion on processing technology, in fact, there are two big quality problem: due to the reaction process with water generated easy forming pinhole and surface defects; Due to the bare a nitrogen atom and yellowing. And this two problems can be properly solve through the selection of the resin.

The HAA system with 95/5 and 95/5 two main types of polyester resin. A lot of people who used the TGIC that convert T105 just changed a kind of crosslinking agent, tend to be in original new powder resin base directly. But it is made a serious mistake.

You know this kind of resin is designed for TGIC, as described above for TGIC activity itself is bad, so need to match the activity of resin. While T105 activity itself is larger, and the reaction to drain the moisture of the reaction. So reaction resin neither too rapidly to the molten coating liquid to fully the flow of time, no reaction of water vapor to set aside enough room for discharge, and numerous coating and pinhole defects. Most of the polyester film thickness 90 um surface generating pinhole, and surface effect basic are better.

Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd 

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