Water-based Thermal Imaging System

In recent years, the CTP technology has been in the stage of vigorous development because of its higher speed, better printing quality. Thermal CTP technology has the fastest developing speed, CTP plate as one of the important factors is developing in the direction of convenient operation, cost saving and environmental protection. Based on the background, a free treatment thermal CTP imaging system with excellent water-soluble, stability, easy preparation and matching was designed.In this study, we focused on dispersing phenolic resin-containing solid particles in water to get stable emulsion in a wish to develop a thermo-sensitive composition based on the emulsion. The main ingredients of the dispersion are:phenolic resin, an infrared-sensitive dye, crystal violet and polymer dispersing agent PVP (Poly vinyl-pyrrolidone). Two methods were employed to prepare the water dipersion:(1) Spray drying-homogenizer method. Sold particles were firstly prepared through spray drying of an ethyl acetate solution of phenolic resin (nearly 20 wt.%), the infrared-sensitive dye and crystal violet, which were then dispersed in PVP water solution through high-speed and high-pressure homogenization. (2) Direct emulsification of organic solution. An acetone solution (about 20wt.%) of phenolic resin, an infrared-sensitive dye, crystal violet was prepared and then added drop-wise to the PVP water solution under high-speed agitation and further treated with high-speed and high-pressure homogenization. Laser particle size analyzer was used to measure the particle size and trace the dispersion procession. Finally, the prepared emulsion was used to prepare laser thermal imaging films and preliminary study showed that the prepared emulsion might be used to developing water-developable imaging composition. But the result is not very ideal.In addition, another kind of thermo-sensitive laser imaging system based on affinity-switching core-shell micro-particles was studied. Firstly, two amphiphilic block copolymers were prepared through live radical polymerization. One copolymer was used as reactive emulsifier for the preparation of nano-particles through soapless emulsion polymerization; another is used as film-forming material in a laser-imageable thermo-sensitive latex film which was formed mainly by the nano-particle and a water-soluble IR-sensitive dye.