Issue 10/2015 - Development of a new polythiol curing agent

A few days ago, the research team of Ningbo Institute of Materials of the Chinese Academy of Sciences has initially developed a latent polymercaptan curing agent
.
The research team intends to promote the latent polymercaptan curing agent to the field of high solids and powder coatings, and relevant research is ongoing
.

Currently, there are a variety of common methods
for the synthesis of thiol compounds.
These methods have the limitations
of multiple steps, complex process, strong alkaline reaction system, long-term acidolysis, high risk of raw materials, easy formation of disulfide bonds, and high production costs.
Finding a method that is not strong acid and base, mild conditions, and suitable for large-scale preparation has become a challenge
for the synthesis of thiol compounds.
In the past, the method of acetyl group transfer to generate sulfhydryl groups had a low overall yield and has been unpopular
.
Researchers from Wu Xuedong research team at Ningbo Institute of Materials tried organic amimines with weaker alkalinity as catalysts
.
The results show that in chloroform, dichloromethane, methanol and other organic solvents, under the condition of 20~30 °C, triethylamine, methyl diethylamine, etc.
can catalyze this reaction rapidly to obtain the corresponding mercaptan.

The reaction conditions are mild and fast, almost no disulfide bond formation, and the thiol yield > 90%.


Based on this result, the research team recently developed a latent polythiol curing agent
.
The traditional polymercaptan curing agent has the outstanding characteristics of low temperature and rapid curing, low toxicity, high gloss and high light retention, but its application is severely limited
due to the shortcomings of foul odor, crusting and high cost.
The new latent polythiol curing agent inherits the advantages and overcomes the disadvantages
.
(Letter)