Study Of Emulsion Type Polyacrylate Glazing Paint

Water-based glazing has became one of the main ornamental postprint technology used in presswork because of its environmental friendly, economy and easily removed performance from print materical. Glazing paint is not only the necessary materical of the glazing process, but also the important factor to effect the glazing quality of presswork. But, the chemical structure property of the film-forming material of the water-based glazing paint leads to poor water resistance, heat resistance and mechanic properties of the paint, which restricts the application widely of water-based glazing paint in presswork. In order to improve the water resistance, mechanical property and thermal property of the emulsion glazing paint, crosslinking core-shell structured polyacrylate emulsiones were synthesized by batch seeded emulsion polymerization and pre-emulsification polymerization with PETA and PET4A as crosslinking agents, which would promote the glazing paint to get a good printability and wide application.Chemical structure and micromorphology of modified polyacrylate were characterized by FTIR and TEM, respectively, with PETA as functional monomer. In accordance with the gel rate and monomer conversion rate, the optimized process of emulsione polymerization was determined:when the m(MMA):m(BA)=32:43, m (PETA)=1.5%total monomer mass, m(core):m(shell)=3:2, and m(SDS):m(OP-10)=1:2, and m(SDS+OP-10)=2.5%total monomer mass, reaction temperature78℃, monomer droplets time1.5h-2.0h, and kept temperature30min after reacting, the stability of emulsion systems was desirable. When the dosage of PETA was1.5%of total monomer mass, water resistance and mechanical properties of modified emulsion film were significantly improved. The water absorption capacity of modified emulsion film declined21.7%, water contact angle was89.3°, tensile strength at break increased0.15MPa, and elongation at break increased15.8%; and the heat resistance was improved obviously,5%,30%and50%weight loss temperature of modified emulsion increased35℃,53℃and63℃, respectively.Chemical structure and micromorphology of modified polyacrylate were also characterized by FTIR and TEM, respectively, with PET4A as functional monomer. When the dosage of PET4A was1.0%of total monomer mass, there were significant improvements in water resistance and heat resistance of modified emulsion film. The water absorption capacity of modified emulsion film declined23.4%, water contact angle was89.5°, and5%,30%and 50%weight loss temperature of modified latex increased35℃,100℃and112℃, respectively. And there was a little difference in mechanical properties, tensile strength at break increased0.15MPa, while elongation at break increased only9.9%.Finally, glazing paint were compounded by the orthogonal design,with modified emulsions by PETA and PTE4A as the main film-forming material, respectively. The gloss factors of the glazing paint were analyzed and the formulations were optimized:when PETA was chosen as functional monomer, solvent18%～22, emulsion55%～62%, water soluble resin17%～21%, additives2%～4%; and when PET4A was chosen as functional monomer, solvent16%～20,emulsion60%～68%, water soluble resin15%～19%, additives2%～4%;according to the repeated experiments, it was concluded that comprehensive properties of modified polyacrylate glazing paint were improved greatly. Test results also showed that glazing paint possessed the better printing ability, water resistance, mechanical property and thermal property.