Study Main Properties of Two Systems Watermark Varnish

In order to obtain good watermark on paper by printing, vegetable oil system and UV light-curing system watermark varnish were prepared by changing the type of vegetable oil, prepolymer and monomer, then test its permeability and refractive index, study the effects of these components on the performance of watermark varnish. Print watermark varnish by screen printing to examine the watermark. The results show that watermark varnish prepared with different type of vegetable oil has different permeability, but refractive index is very close. Adding prepolymer can improve permeability and refractive index of vegetable oil system watermark varnish. If the specific gravity of prepolymer and monomer is greater, permeability of UV curing system watermark varnish is higher. If refractive index of prepolymer and monomer is bigger, refractive index of varnish is bigger. Printing effect of UV curing system watermark varnish is better than vegetable oil system watermark varnish.