Water-based inks are mainly composed of hydrophilic acrylic resins, pigments, water and additives. In the conventional alkaline deinking process, hydrophilic acrylic resins cause great difficulty in deinking waste paper. The main reason is that The ink particles peeled off from the fibers in the pulping stage are particularly finely dispersed, have an average particle diameter of about 0.2-1.0 μm, and are hydrophilic, which seriously affects the deinking efficiency. There have been studies to improve the deinking performance of newsprint and magazine papers printed using aqueous inks by optimizing the deinking process and the use of suitable deinking agents to improve the deinking efficiency. However, conventional alkaline flotation washing and deinking techniques are not suitable when dealing with over 10% of printed waste paper for aqueous ink prints. In order to solve this problem, this subject has carried on the preliminary discussion from changing the ink component, has carried on the printing and the deink experiment on the newsprint paper to the preparation water-based light-curing ink, this ink is a kind of new type water-based ink, the ink connection material With a hydrophilic group, can be dispersed in water under alkaline conditions; printed on paper, the ink under the irradiation of ultraviolet (UV) can be quickly cross-linked film curing, complete the drying process. Printing production can now be performed on flexographic printing presses with UV devices. When this ink-printed newspaper is deinked under normal alkaline conditions, due to the cross-linking reaction of the connecting material, the ink particles peeled from the fiber will not be disintegrated into very fine particles like ordinary aqueous ink, if the ink is used Particle control in the range of 20-200 microns suitable for flotation deinking can greatly improve deinking efficiency. 1 experiment 1.1 Experimental Materials and Equipment Newsprint: quantitative 46.3g/m3, whiteness 57.8%, opacity 94.3%, taken from Shandong Huatai Paper Group; water-based light-curable ink: homemade; oil-based news ink: produced by Taiyuan Ink Factory; water-based flexo ink: Shenzhen cloth Reiter, Industrial Co., Ltd. production; Exhibition wheel: Shanghai Institute of Printing Technology Manufacturing; 518 reflective densitometer: US-made X-Rite company; UV curing machine: domestic, illumination distance 15 cm, light intensity 80W/cm; YQ-Z-48B whiteness tester: domestic; H-272M pulper; L-100 flotation deinking instrument; FI101 square type film maker; residual ink scanner: Canadian production. 1.2.1 Analog Printing of Different Types of Inks Printing inks of different types are printed on newsprint using a color wheel. The ink coverage rate is 25%. Oil-based news inks and water-based flexographic inks are naturally dried and water-based light-curable inks are printed. Immediately afterwards, the UV curing machine was used for irradiation and drying. In order to ensure the consistency of different types of ink ink film thickness, the ink density of the ink film is controlled by the printing product optical density method, and the ink amount of each ink is adjusted so that the optical density of the product after drying is 1.35-1.45, and the optical density is measured with a reflection densitometer. . Printed paper is stored for 2 months. 1.2.2 Disintegration of Paper The paper printed in 1.2.1 was torn to 25mm*25mm and placed in a sealed bag to balance the moisture. Pulping in the high-refiner pulper, first add a certain amount of hot water in the pulper, adjust the pulping temperature to 55 degrees Celsius, and then add the metered NaOH solution, Na2SiO3, deinking agent, H2O2, and 80g absolute dry fiber News paper. 1.2.3 Flotation Divide the disintegrated slurry to 1%, pour it into the waste paper flotation deinking machine, start the circulating pump for 2 minutes, open the inlet valve, adjust the gas flow 0.08-0.12 m3/h, and float at room temperature. 1.2.4 Washing The flotation slurry was washed to a concentration of 0.5% and concentrated once by 80 mesh copper mesh washing. 1.2.5 Tablets The disintegrated pulp or flotation-washed pulp was copied on a square-shaped sheeter to a basis weight of 60 g/m2. 1.3 Analysis Methods A whiteness meter was used to determine the whiteness of the paper. Analysis was performed using a residual ink scanner in accordance with TAPPI standard T568pm-99, and the resolvable ink particle size was 8-678 microns. 2 Results and Discussion This experiment explored the deinking performance of water-based photo-curable inks under current conventional alkaline conditions. The chemical conditions simulate conventional deinking. The amount of chemical used (relative to absolute dry paper) is NaOH1%, Na2SiO32%, and deinking agent, respectively. 0.4%, H2O21%. 2.1 According to the experimental data, in the conventional alkaline deinking process, the suitable deinking conditions for waterborne photocurable inks are pulp concentration 10%, pulping time 20 min, stirring speed 1500 r/min, and flotation time 15 min. 2.2 Under suitable deinking conditions, the deinking efficiency of waterborne photocurable inks is close to that of oil based news inks and superior to waterborne flexographic inks. 2.3 Water-based photo-curing inks change the formulation and drying methods of traditional water-based inks, providing a new idea for solving the problems of water-based ink deinking.
1.2 Experimental methods