The mechanism of crosslinking (solidification) of coating coating

The mechanism of crosslinking (solidification) of coating coating (1) NCO/OH type two-component polyurethane coating:

Crosslinked coating process is the main chemical reactions - NCO and - OH reaction, formed by ammonia ester bond in the presence of catalyst, the ammonia ester bond in the secondary active on the nitrogen atom of hydrogen will affections and excess - NCO base reaction of formic acid ester bond. Under certain conditions, the reaction can be developed rapidly, until it runs out of the remaining NCO.

As you can see, NCO/OH type two-component polyurethane coating curing is the result of a variety of chemical reaction, generate different chemical bonds, the coating with a variety of structures, thus obtain the all kinds of good performance.

The mechanism of crosslinking (solidification) of coating coating (2) crosslinked solid type fluorocarbon paint:

The cross-linking reaction of the coating is similar to the NCO/OH type two-component polyurethane coating, which is the negative oyl in fluorocarbon resin and the -ncokey reaction in the fatty group HDI diurea.

Theoretical analysis of performance gap. The cross-linking reaction of these two coatings is found to be the same mechanism, both of which are the chemical reactions of -nco base and -oh group. But after crosslinking type of fluorocarbon crosslinking F elements contained in the molecular structure and C - F chemical bonds, now some reference data to illustrate the importance of containing such bonds and elements. The c-f key can be a basis for high tolerance coatings for fluorocarbon paint.

The c-f bond can (484kJ/mol) the > Si -o bond energy (422kJ/mol) the > c-h bond can (410kJ/mol) the > c-c bond energy (368kJ/mol) the > c-o bond energy (357.5 kilojoules per mole) the > c-o key energy (304kJ/mol).

Sunlight ultraviolet wavelength is 220 ~ 400 nm, 220 nm wavelength of the photon energy of 544 kj/mol, only less than 220 nm photon can make fluorocarbon C - F keys, and the sun is less than 220 nm photon ratio is small, therefore, sunshine almost has no effect on painting.




Chinese name: Diethyl toluene diamine(DETDA)

Diethyltoluenediamine packing： net weight 200KG/ galvanized iron drum (a small cabinet pallet loaded 16 tons), 1000KG/IB barrels (a small cabinet loaded 18 tons or 23 tons of ISOTANK).


Fluorine atom radius is small, only less than hydrogen, and the greatest electronegativity, therefore the compact structure of the film, in regard to chemical show high thermal stability and chemical inertness. Hydroxyl acrylic polyurethane coating, due to the molecular structure in the chemical bonds is C - C, C, O, C - N chemical bonds, compared with C - F key, the key can be small, the atomic radius of the element are also contained F atoms, and electronegativity is smaller than F atoms, as a result, coating weathering resistance, chemical corrosion resistance and other properties are worse than fluorocarbon lacquer, the reason is that the.

To verify the room temperature cured fluorocarbon lacquer and aliphatic hydroxyl acrylic polyurethane coating differences in performance, the natural exposure and bolt, artificial accelerated aging, resistance to salt fog, 10% sulfuric acid immersion, 10% sodium hydroxide soak SO2, NO2, HCl gas and gas test.

2 supporting system (fluorocarbon coating and packages, compared to 1 (acrylic polyurethane coating system) has a more outstanding weather resistance, after 3456 hours of artificial accelerated test, coating light rate is over 90%.

It is better than that of acrylic polyurethane coating for the protection of light performance and salt resistance.

0 indicates no bubbles, no powder, no rust; 1S2 indicates that the panel has several visible blisters under normal vision. 4S2 represents a large number of visible bubbles.

By artificial accelerated aging and natural exposure, salt fog resistance, acid and alkali soaking and acidic gas gas phase trials of fluorocarbon coating compared with the acrylic polyurethane coating, showing the best anti-corrosion performance, is a new type of super durable heavy-duty coating.

Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd 

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