The ability to deink paper – basically, to break ink and coatings from it – is very important for renewable recycling of it. Good deinkability is aprerequisite for using used paper to make graphical papers and hygienic paper goods. Efficient procedures are available in these days for eliminating aqueous coatings and sheetfed offset inks. It is even more difficult to achieve good results with UV-cured inks and coatings, the liquid toners used in digital printing, and inkjet inks.
Ink that is removed from recycled pulp can be burned to generate energy to run the mill, or sold to create such useful substances as compost or gravel for roads. A single piece of paper may contain new fibers along with fibers who have already been recycled once, twice, or several times. Papermaking fibers can typically be recycled 5-7 times before they become too short to be recycled once more. Effective recycling requires clean recovered paper that's free of contaminants such as food, plastic, metal, and other trash. Contaminated paper can introduce pollutants and bacteria into the recycling process. Moreover, different grades of paper - corrugated boxes, newspapers, and office paper - must be kept separate, because the different grades of recovered paper are used to make specific types of recycled paper products.
Many of the pigments utilized in ink include metallic items that happen to be risky to human health and the environment such as cadmium, chromium, lead and mercury. Conventional printing inks are petroleum-based and used with alcohol-based solvents. As alcohol and petroleum evaporate Volatile Organic Compounds (VOCs) are emitted. VOCs symbolize ecological pollution and a health hazard to pressroom workers. In terms of atmospheric air pollution, VOCs react with nitrogen oxides in the existence of sunlight to create ozone pollution or photochemical smog.
Offset inks generally consist to 30 % of mineral oils. Using eco-inks, also known as eco-solvent inks and green inks, can cut down at the consumptionof fossil fuels. These products use modified vegetable oils instead, such as linseed or soy esters. Eco-inks are already widely used in some markets.The differences in reproduction quality and processing are hardly evident.
All major European producers are involved in the voluntary commitment made by the EU ink industry to protecting health and ensuring product safety. Soya and vegetable based inks also help the environment due to better ease of removal from wastepaper while de-inking for recycling.Also with UV inks a few producers have succeeded in changing up to30 % of the compounds that go into their formulations with renewable raw materials. From an ecological perspective, in connection with packaging it is relevant that only incredibly little amounts of ink ingredients migrate from the printed surface into the substrate.
Print coatings may also be regarded as unpigmented inks. Like eco-inks,it is therefore also straightforward to use vegetable oil derivatives insteadof mineral oils to create them. Dispersion and UV coatings are considerably less conducive to substituting renewable raw materials.