Properties / Applications: Bayhydrol® UV 2280 is used in the formulation of aqueous UV-curing coatings, especially for application on wood/wood materials. Generally speaking, the coated surfaces can be sanded before UV curing. Additions of 1 - 2.5 % by wt. photoinitiator, calculated on the solid binder, have proved suitable for initiating the curing reaction. The viscosity is adjusted by the addition of polyurethane thickeners. If antifoams are used, they should be thinned in solvents, especially if application is by curtain coating. Matting agents and additives can be dispersed directly in the product using a dissolver. Bayhydrol® UV 2280 is easily matted using standard matting agents. As a rule, the coatings should be colored using aqueous pigment pastes. After evaporation of the water, the coatings can be cured at a belt speed of up to 10 m/min per 80 W/cm lamp. Ga-doped lamps and special photoinitiators are normally used in the curing of pigmented systems. To ensure optimum curing, it is important that the film contains no water and that thermal predrying has taken place. Depending on the formulation, the paint films are physically dry and sandable after evaporation of the water. However, they have no chemical or mechanical resistance. UV curing yields films with very good mechanical and chemical resistance. Bayhydrol® UV 2280 is also characterised by its good adhesion on many metallic substrates. Combination with Bayhydur® allows the formulation of aqueous dual-cure systems.

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