LF-90 paint anti-mold agent to effectively anti-mold, paint anti-mold agent must not only be dispersed evenly in the paint, but also to ensure that the amount of added anti-mold agent small inhibition concentration (MIC).
For example, Nordes EPW paint film anti-mildew agent in the preparation of interior anti-mildew coating formula to add 0.3% of anti-mildew agent, in the preparation of exterior anti-mildew coating formula to add about 0.5% of anti-mildew agent, in high temperature and high humidity environment and other circumstances should also be increased.
The resonance structure (C) has intramolecular hydrogen bonds, which is very similar to the situation of 2-hydroxybenzophenone UVA. It should be noted that only excited singlet states are generated after light absorption, and there is no excited triplet state, so there is no excited triplet state. The inter-system crossing process between the state and the singlet state. After 2-hydroxyphenylbenzotriazole absorbs photons, the center of the high electron cloud density is transferred from the phenolic oxygen atom to the nitrogen atom, and the basicity of the nitrogen atom center is enhanced! 35. The proton is abstracted from the phenolic hydroxyl group, roughly as follows The principle of photoisomerization is very similar to that of 2-hydroxybenzophenone.
In addition, the UVA based on the oxalyl dianilide structure has a lower absorption wavelength range (280~320nm), which may have less shielding effect on the photoinitiator in the photocurable coating. Due to the lower light absorption wavelength, there will be no color problems by itself, and it is suitable for varnishes and light-colored systems. Moreover, the oxalyl dianilide UVA has only a short excited singlet lifetime and has no free radical trapping effect , and its light stabilization mechanism is similar to the sasol wax a2 aforementioned two types of UVA. There is a photo-induced proton transfer process and degrades harmful ultraviolet rays.
The mechanism is expressed as follows:
Commercial oxalyl dianilide UVA often has substituents on the benzene ring to meet the requirements of compatibility, anti-migration, low volatility, and low toxicity, while also improving the efficiency of action.
The maximum absorption wavelength of the cyanoacrylate series UVA is at 310~320nm. Because the structure does not contain phenolic hydroxyl groups, it has good chemical stability. Through the structural change of the ester group, good compatibility with the coating resin can be obtained. There are light stabilization applications in coating systems such as urea-formaldehyde resin, epoxy resin, polyester, polyurethane, and nitrocellulose.
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