1, UV-curable waterborne coating film-forming mechanism of

Surface Treatment Huicong As mentioned earlier, the formation mechanism of water-based UV-curable coatings for the essential, only to clarify the solidification of the film-forming process, the main film-forming resin can be triggered Jing, emulsifier, etc. areas such as selection and synthesis, to find a theoretical basis.

SweeYongchee such as law by DSC and FTIR Study of the UV-curable dry film of latex. Proof of UV-curable water-based latex drying in a vacuum dry form, although the photoinitiator in the membrane were fixed, but in the UV irradiation, there is still cross-linking reaction took place. TomScherzer such as near-infrared reflectance spectroscopy with detection of the conversion rate of double bond-line monitoring of UV-curable acrylate coating process and its quality. If you can use a low-power UV lights, slow down the process of curing film, and then use a combination of analytical instruments (eg, UV curing unit and a combination of atomic force microscope) photo of the micro-film the entire process of curing, research into more convenience.

2, the development does not require pre-heating, the direct use of the water-based UV-curable coatings

Water-based UV-curable coatings in the UV-curable prior to baking in general need to further speed up the evaporation, even electrophoresis of UV-curable coatings, also need a "flash" process to remove excess moisture. This water-based paint throughout the lengthy curing process, energy consumption increases.

In addition, the UV-curable water-based paint after infrared drying Photoinitiators has been fixed in the coating, the time after UV irradiation, further cross-linking reaction will result in internal stress, so that deterioration of film properties . Edward Island, such as Huang Xing used to light-cured, and then heat curing the ways in which stress dissipation, obtained by coating a relatively high thermal stability.

However, the coating itself is a poor conductor of heat, the polymerization reaction will release heat to temperature, and generally used in ultra-violet light source have a large amount of infrared radiation, can make use of these thermal evaporation and reaction curing at the same time. There are two ways that, first, improve the solid content to reduce the evaporation of the initial time. Ai synthesized according to solid congruent with 72% of low viscosity high solid content of (PMMA / BA / AA) latex, which is equivalent to direct access to the film

Medium-term. Second, the introduction of hyperbranched polymer (Hyperbranchedpolymer), to enable more rapid response and shorten the curing time film. And hyperbranched polymers have demulsification role, after the water and emulsifier demulsification will float to the surface of resin, which is equivalent to speed up the evaporation of water. AnilaAsif will be more water-soluble functional groups to introduce the ultra-branched polyester polyurethane acrylate polymer emulsion to reduce the resin viscosity, curing rate to increase. The complex shape of the workpiece in place less than direct UV curing it is very difficult, the current study can be a double-curing water-based UV-curable coatings, as a result of resin needed by adding two kinds of initiator at the same time (for example, photoinitiators and thermal induced agent), so that the coating is too complicated to develop. For millions of ultra-molecular-weight polymer can be natural or heat-curing dry film, which is equivalent to a dual curing.

3, Synthesis of multi-functional group containing polymer prepolymer

Non-traditional light-cured solvent-based coatings difficult to both high hardness and high flexibility, with the other hand, UV-curable water-based paint can be used for water-borne polymer dispersion, the viscosity and polymer molecular weight has nothing to do, from the fundamental solution to the light-cured coatings with high hardness and high flexibility contradiction. Emulsion crosslinking with functional groups than in the water of the emulsion. , Alkali resistance, boiling water, and humidity and so on have increased reactive polymer emulsion and water-soluble coating composition and the production of industrial coatings in one direction. But how in the molecular weight of the polymer emulsion millions more than the introduction of functional groups, there are still many difficulties, because the polymer is wrapped emulsifier. Preliminary synthesis JOHANODEBERG containing unsaturated functional groups of the polymer molecules, so that when the UV-curable film-forming do not need to join the other multi-functional monomers. The literature in the emulsion polymerization process of the introduction of functional groups, the reaction after the film has been cross-linked structure with the coating. Ji issued if carbon-carbon double bonds with functional groups such as the emulsifier to emulsifier can also participate in the response, it is even more perfect.

4, nano-pigments and the introduction of filler

Generally made of UV-curable coating varnishes, pigments and fillers because there is reflection on the role of ultraviolet light, so that curing the underlying membrane have been hampered, but in some cases, the color is necessary, for example, a UV-curable important applications in optical coatings, we need to use different colors of paint marking the type of fiber. Nano-filler in paint and light by comparison of the general good, there should be hope that applies to water-based UV-curable coatings. Iv Ai congruent according to research in the introduction of synthetic latex nano-titanium dioxide. Chen called such as the introduction of the nano-SiC UV-curable resin, nano-materials and matrix resin and the interaction between the evenly dispersed in the matrix resin. Nano-composite resin and resin matrix, compared to better physical properties.

5, Prolamin of UV-curable coatings

Completely to ethanol as solvent instead of water the UV-curable coatings, not reported in the literature, but in the actual industrial production has been applied. In most cases, ethanol as a cosolvent, such as Wang Cundong iv used the water / ethanol (volume ratio 80:20) mixed solvent, resulting in a UV-curable epoxy acrylate flexible membrane has been greatly improved , and the performance of other less affected. Water-soluble UV-curable coatings as a result of the preparation process of the need for preparation of water-based resin, without solvent-based UV-curable coating preparation can not be too high molecular weight (generally believed that more than 100,000 molecular weight, it is a solid). Prolamin of UV-curable coating of the advantages of a combination of both, and ethanol as solvent is also very environmentally friendly, as a result of surface tension of ethanol than water in small, on a stronger substrate wettability of the substrate on the role of the oil has dissolved, So get a better coating adhesion. (Source: "UV-curable waterborne coating" Author: Zhou Xuesong)