UV light curing powder coatings and their advantages
The main feature of UV powder coatings is that the process is divided into two distinct phases, with no early curing of the resin occurring during the melt leveling phase, thus providing ample time for the coating to fully level and expel air bubbles; the use of UV curing technology can significantly reduce the heating and curing process temperatures and improve production efficiency. The use of UV curing technology significantly reduces the temperature of the heating and curing process, increasing productivity and making UV coatings suitable for all types of heat sensitive substrates.
Compared to UV-cured liquid coatings, light-cured powder coatings have no active thinner, low film shrinkage and high adhesion to the substrate. Light-cured powder coatings can be applied in one coat to form a coating of excellent quality with a thickness of 75~125μm. Therefore, light-curing powder coatings are also solvent-free and environmentally friendly, and have higher technical, economic and ecological advantages than thermosetting powder coatings and UV liquid coatings.
Light-curing powder coatings consist of a main resin, photoinitiator, pigments, fillers, various additives and so on. The main resin is the main film-forming substance of light-curing powder coatings, and is the main component that determines the nature of the coating and the performance of the coating film. Formulation of light-curing powder coatings, on the one hand, the resin is required to give the powder good storage stability, on the other hand, the raw materials used must be at a lower temperature (such as 100 ℃ under) with the required melt viscosity, in order to ensure that the coating in the light curing before and light curing process with good flow and leveling properties, followed by light curing reaction below 120 ℃. The main resins that have been developed are generally unsaturated polyesters, vinyl ether resins, unsaturated polyester acrylates, urethane acrylates, epoxy resins etc.
The addition of hyperbranched resins can reduce the glass transition temperature of the resin, resulting in improved rheological properties and coating film performance. Hyperbranched polymers have high functionality, spherically symmetrical three-dimensional structure and inter- and intramolecular structure characteristics such as chain entanglement, low viscosity, good inter-solubility, high activity, and it is easy to modify the surface of multiple functional groups and other characteristics, can be used in coatings as film-forming substances, viscosity modifiers, etc., to improve the performance of the coating film.
The initiator can be selected from a wide range of species, such as the use of α-hydroxy ketone (AHK) and double acyl phosphine oxide (BAPO) combination, AHK because of its insensitivity to oxygen-blocking and the resulting coating has good surface properties, and in its structure of the benzene ring substituent on the opposite side of a polar hydroxy ethyl oxygen substituent and make the compound in UV-curable powder coatings extrusion and film-forming temperature under the low volatility. BAPO has two significant absorption peaks at about 370nm and 400~450nm, with high photoreactivity and absorption characteristics, can meet the needs of deep curing; cationic curing system can be used sulfonium salt, iodonium salt, etc.
UV Photoinitiator Same series products
| Product name | CAS NO. | Chemical name |
| lcnacure® TPO | 75980-60-8 | Diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide |
| lcnacure® TPO-L | 84434-11-7 | Ethyl (2,4,6-trimethylbenzoyl) phenylphosphinate |
| lcnacure® 819/920 | 162881-26-7 | Phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide |
| lcnacure® 819 DW | 162881-26-7 | Irgacure 819 DW |
| lcnacure® ITX | 5495-84-1 | 2-Isopropylthioxanthone |
| lcnacure® DETX | 82799-44-8 | 2,4-Diethyl-9H-thioxanthen-9-one |
| lcnacure® BDK/651 | 24650-42-8 | 2,2-Dimethoxy-2-phenylacetophenone |
| lcnacure® 907 | 71868-10-5 | 2-Methyl-4′-(methylthio)-2-morpholinopropiophenone |
| lcnacure® 184 | 947-19-3 | 1-Hydroxycyclohexyl phenyl ketone |
| lcnacure® MBF | 15206-55-0 | Methyl benzoylformate |
| lcnacure® 150 | 163702-01-0 | Benzene, (1-methylethenyl)-, homopolymer,ar-(2-hydroxy-2-methyl-1-oxopropyl) derivs |
| lcnacure® 160 | 71868-15-0 | Difunctional alpha hydroxy ketone |
| lcnacure® 1173 | 7473-98-5 | 2-Hydroxy-2-methylpropiophenone |
| lcnacure® EMK | 90-93-7 | 4,4′-Bis(diethylamino) benzophenone |
| lcnacure® PBZ | 2128-93-0 | 4-Benzoylbiphenyl |
| lcnacure® OMBB/MBB | 606-28-0 | Methyl 2-benzoylbenzoate |
| lcnacure® 784/FMT | 125051-32-3 | BIS(2,6-DIFLUORO-3-(1-HYDROPYRROL-1-YL)PHENYL)TITANOCENE |
| lcnacure® BP | 119-61-9 | Benzophenone |
| lcnacure® 754 | 211510-16-6 | Benzeneacetic acid, alpha-oxo-, Oxydi-2,1-ethanediyl ester |
| lcnacure® CBP | 134-85-0 | 4-Chlorobenzophenone |
| lcnacure® MBP | 134-84-9 | 4-Methylbenzophenone |
| lcnacure® EHA | 21245-02-3 | 2-Ethylhexyl 4-dimethylaminobenzoate |
| lcnacure® DMB | 2208-05-1 | 2-(Dimethylamino)ethyl benzoate |
| lcnacure® EDB | 10287-53-3 | Ethyl 4-dimethylaminobenzoate |
| lcnacure® 250 | 344562-80-7 | (4-Methylphenyl) [4-(2-methylpropyl)phenyl] iodoniumhexafluorophosphate |
| lcnacure® 369 | 119313-12-1 | 2-Benzyl-2-(dimethylamino)-4′-morpholinobutyrophenone |
| lcnacure® 379 | 119344-86-4 | 1-Butanone, 2-(dimethylamino)-2-(4-methylphenyl)methyl-1-4-(4-morpholinyl)phenyl- |
| lcnacure® 938 | 61358-25-6 | Bis(4-tert-butylphenyl)iodonium hexafluorophosphate |
| lcnacure® 6992 MX | 75482-18-7 & 74227-35-3 | Cationic Photoinitiator UVI-6992 |
| lcnacure® 6992 | 68156-13-8 | Diphenyl(4-phenylthio)phenylsufonium hexafluorophosphate |
| lcnacure® 6993-S | 71449-78-0 & 89452-37-9 | Mixed type triarylsulfonium hexafluoroantimonate salts |
| lcnacure® 6993-P | 71449-78-0 | 4-Thiophenyl phenyl diphenyl sulfonium hexafluoroantimonate |
| lcnacure® 1206 | Photoinitiator APi-1206 |