Study on Deinking Performance of Waterborne Photocurable Ink
We are a big printing company in Shenzhen China . We offer all book publications, hardcover book printing, papercover book printing, hardcover notebook, sprial book printing, saddle stiching book printing, booklet printing,packaging box, calendars, all kinds of PVC, product brochures, notes, Children's book, stickers, all kinds of special paper color printing products, game cardand so on.
For more information please visit
http://www.joyful-printing.com. ENG only
http://www.joyful-printing.net
http://www.joyful-printing.org
email: info@joyful-printing.net
The water-based ink is mainly composed of hydrophilic acrylic resin, pigment, water and auxiliary agent. In the conventional alkali deinking process, the hydrophilic acrylic resin brings great difficulty in deinking the waste paper, mainly because The ink particles which are peeled off from the fibers in the pulping stage are dispersed particularly finely, have an average particle diameter of about 0.2 to 1.0 μm, and are hydrophilic, which seriously affects the deinking efficiency.
It has been studied to improve the deinking performance of newsprint and magazine paper printed with water-based inks by optimizing the deinking process and using a suitable deinking agent, thereby improving the deinking efficiency. However, when dealing with printing waste paper having more than 10% of aqueous ink prints, it is not suitable to use conventional alkali flotation washing deinking technology.
In order to solve this problem, this topic has carried out a preliminary discussion on changing the ink composition. The prepared water-based photocurable ink was printed and deinked on newsprint. The ink is a new type of water-based ink and ink connecting material. It has a hydrophilic group and can be dispersed in water under alkaline conditions. When printed on paper, the ink can be quickly crosslinked to form a film under ultraviolet (UV) irradiation to complete the drying process. Printing production can be accomplished on flexographic presses currently equipped with UV devices.
When such an ink-printed newspaper is deinked under conventional alkaline conditions, the ink particles peeled off from the fibers are not disintegrated into very fine particles like ordinary aqueous inks due to the cross-linking reaction of the binder. The particle control is in the range of 20-200 microns suitable for flotation deinking, which greatly improves the 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-curing ink: homemade; oil-based news ink: Taiyuan ink factory production; water-based flexographic ink: Shenzhen cloth Reiter, Industrial Co., Ltd. production; color wheel: manufactured by Shanghai Printing Technology Research Institute; 518 type reflective density meter: manufactured by X-Rite Company of the United States; UV curing machine: domestic, with a distance of 15 cm, light intensity of 80 W/cm; YQ-Z-48B whiteness measuring instrument: domestic; H-272M pulper; L-100 flotation deinking instrument; FI101 square type paper reader; residual ink scanner: Canadian production.
1.2 Experimental methods
1.2.1 Simulated printing of different types of inks Different types of black inks are printed on newsprint using the color wheel, the ink coverage is 25%, oil-based news inks and water-based flexographic inks are naturally dried, and water-based light-curing inks are printed. Immediately thereafter, it was dried by a UV curing machine. In order to ensure the consistency of the ink film thickness of different types of inks, the thickness of the ink film is controlled by the printing optical density method, and the ink amount of each ink is adjusted to make the optical density of the product after drying 1.35 - 1.45, and the optical density is measured by a reflection densitometer. . The printed paper is stored for 2 months.
1.2.2 Disintegration of paper
The paper printed in 1.2.1 was torn to 25 mm * 25 mm and placed in a sealed bag to balance moisture. In the high pulper, grind the pulp, first add a certain amount of hot water in the pulper, adjust the pulp temperature to 55 degrees Celsius, then add the metered NaOH solution, Na2SiO3, deinking agent, H2O2 and 80g of dry fiber. News paper.
1.2.3 Flotation
Dilute the disintegrated slurry to 1%, pour into the waste paper flotation deinking instrument, start the circulating slurry pump for 2 min, open the intake valve, adjust the gas flow rate 0.08-0.12 m3/h, and float at room temperature.
1.2.4 Washing
The slurry after flotation was rinsed to a concentration of 0.5%, and concentrated by washing with an 80-mesh copper net.
1.2.5 copying
The pulverized slurry or the flocculated washed slurry is placed on a square type sheet reader, and the amount is 60 g/m 2 .
1.3 Analysis methods
The whiteness of the paper was measured using a whiteness meter. The residual ink scanner was analyzed according to TAPPI standard T568pm-99, and the resolvable ink particle size was 8-678 microns.
2 Results and discussion
This experiment explores the deinking performance of aqueous photocurable inks under conventional alkaline conditions. The chemical conditions simulate conventional deinking. The amount of chemicals (relative to dry waste paper) is NaOH1%, Na2SiO32%, and deinking agent. 0.4%, H2O 21%.
2.1 According to the experimental data, in the conventional alkali deinking process, the suitable deinking conditions of the aqueous photocurable ink are pulping concentration 10%, pulping time 20min, stirring speed 1500r/min, flotation time 15min.
2.2 Under suitable deinking conditions, the deinking efficiency of aqueous photocurable inks is close to that of oil-based news inks, which is superior to aqueous flexographic inks. 2.3 Water-based photocurable inks have changed the formulation and drying methods of traditional water-based inks, providing a new idea for solving the problem of deinking of water-based inks.