To Explore the Development Trend of Green Ink2012.06.28 12:39
To study the environmental protection ink, we should understand the harm of traditional solvent-based inks to us first:
Focus on the development trend of green ink
Printing ink is composed of pigments, binders, solvents and the adjuvant. Among them, organic solvent of the binders has serious damage on the human body. The organic solvent can dissolve many natural resin and synthetic resin, is an important composition part of the ink, but it will injure the body and subcutaneous fat. Long-term contact will make the skin dry, rough, and if it infiltrated into the skin or blood vessels, with blood it will endanger human blood cells and hematopoietic function.
In gravure printing and Flexo solvent-based inks, organic solvent content reaches 40%~60%. Its dry form is evaporation drying. The large amount evaporation of organic solvent can cause air pollution. If it is breathed into the windpipe, bronchial, lung or upon vascular, spread from lymphatic to other organs, may even cause chronic poisoning of the human body. At present, strict control are taken to coating, printing ink and a series of commodity VOC content at home or aborad, in order to reduce the harm to human body and environment.
All researchers are up to the development of new environment-friendly ink. At present, the most widely used environmental protection printing ink inland has three main categories, namely, water-based ink, UV curable inks and alcohol-soluble ink.
1, water-based ink
Aqueous ink is used water based resin as binder, senior pigment or dye as colorant, water as solvent, a small amount of ethanol as cosolvent, accompanied with a variety of additives through fine grinding and deployment to form a kind of liquid printing inks. Compared with the traditional solvent-based inks the biggest difference lies in the water-based ink solvent used in water and ethanol, VOC content is extremely low, also little pollution to environment.
Environmentally friendly water-based ink at present in our country’s main application field is the flexo printing, gravure printing and screen printing. Because of the VOC content in the solvent is quiet low, not only have less pollution of the atmospheric environment, but also reduce the printed surface residual toxicity, so the application of water-based ink products are the majority of packaging products, among them food packaging, alcoholic drinks and tobacco packaging, toy packaging has quite large proportion.
Although the water-based ink has been widely used in coated paper, white paperboard, corrugated paper and plastic film printing, however due to its cost, many packaging manufacturers are reluctant to use it; furthermore the ink printing still exists some problems, such as the ink is easy to dry on the roller, which affects the ink’s uniformity; ink’s easy foaming effect impact on the color density; bad water fastness, solvent resistance and abrasion performance. These need further research and development of scientific research personnel, so that the ink would achieve more swift and violent development.
2, UV curing ink
UV curing ink is a kind of energy saving environment friendly printing ink which rapidly developed in recent years, also called UV ink. This ink makes use of ultraviolet radiation to cause ink binders’ polymerization to dry. It does not contain volatile organic solvent, no solvent pollution. The water-based UV ink is the new direction of the UV ink research and development. With water and ethanol as a diluent, such that toxicity can be very low under the condition of the low VOC emissions. The water-based UV ink has been successfully developed, and put into use in some printing industrial.
In addition, UV cation-type cured ink can be regarded as a better future of UV ink. Cationic photocuring system more radical UV-curing system is not affected by oxygen inhibition effect, has good surface curing, , less irritation on human skin, small internal stress in the ink layer after curing, small volume contraction, flexibility and good adhesion and other advantages. So it has become the hot subject of ink research and development.
3, alcohol soluble ink
Non-benzene soluble ink which mainly plays a role in gravure printing is a kind of few-pollution ink, mainly used in food, pharmaceuticals, beverages, tobacco and alcohol or and the commodity packaging and printing which contract to human body etc.
Alcohol ester composite inks has low odor, no benzene or ketones, and other characteristics, ink industry has been working to develop such less- pollution alcohol-soluble ink to environmental.
Vegetable oil based ink is an environment-friendly ink used the plant oil instead of the part of petroleum solvent series in the ordinary ink, do not alter other ingredients such as resin, pigment and other constant.
So, in conclusion no matter is the water ink, UV curable inks, alcohol-soluble ink, or soybean oil ink, are all started from the ink component, use environmental protection material to replace the toxic ingredients of the traditional solvent-based inks, its environmental performance is obviously. Environmental protection type ink will be the main market forces of the ink field in the future.
By Le Qi