A thermo-sensitive imaging coating derived from polymer nanoparticles containing infrared absorbing dye

• IR dye in polymer nanoparticles can be synthesized by miniemulsion polymerization.
• Negative image was obtained by IR laser radiation followed with water developing.
• This coating material can be used for developing chemical-free thermal CTP plate.

The present study relates to a method for incorporating a near infrared dye (the absorption maximum at approximately 830 nm, IR-830) into polymer particles via miniemulsion polymerization and the preparation of an infrared laser-imageable coating based on the polymer particles as well as the potentiality in developing environment-friendly computer-to-plate (CTP) precursor. Polymer particles containing the IR-830 were prepared through miniemulsion polymerization technology in the presence of sodium dodecyl sulfate and hexadecanol as the emulsifier blend. Polyvinyl alcohol was used as a water soluble polymer binder resin for the production of latex coatings. Using the above prepared materials as the main components, an IR laser-imageable coating was prepared. Upon computer-controlled laser exposure, the IR dye-containing polymer particles absorb IR laser energy and produce high temperature, causing great changes of the imaged areas of the latex coating. As a result, the imaged areas could not be removed with water cleaning, whereas the polymer particles of the non-imaged areas remain unchanged, and still could be easily removed by water cleaning. When developing with water, negative graphics were obtained. The results of the research can be used in developing chemical-free CTP plates required by green printing industry.

Polymer particles containing infrared (IR) absorbing dye exhibit fairly high sensitivity to infrared laser beam. In this paper, we present the preparation of the IR dye-containing polymer nanoparticles and study the use in lithographic printing plate, which can be imaged using digitally controlled laser output and developed by neutral water. The principles of the laser imaging process are proved by SEM that the IR dye-containing polymer particles fuse and the original structure is broken down.Figure optionsDownload as PowerPoint slide