Use of water-based ink

Water-based inks (Water-based lnk), which are simply called ink inks, are produced by the composite grinding of water-soluble resins, organic pigments, surfactants, and related additives. Due to the absence of volatile organic solvents, water-based inks greatly reduce the emission of organic volatiles (VOCs, the same below), thereby reducing air pollution, improving the environment for printing operators, and contributing to the health of employees. It can completely eliminate certain toxic and harmful substances in solvent-based inks, eliminate the harm to human body and the pollution of packaged goods, and improve the overall environmental quality. It is especially suitable for hygiene conditions such as tobacco, alcohol, food, beverages, medicines, and children's toys. Strict packaging and printing products are required.

In addition, it not only reduces the risk of fire and danger due to static electricity and flammable solvents, but also reduces the residual toxicity of printed surfaces and facilitates the cleaning of printing equipment. Whether it is imported water-based ink or domestic water-based ink, the printing performance and quality cannot reach the standard of solvent-based gravure ink. At present, water-based inks have drawbacks such as non-alkali resistance, non-anti-ethanol and water resistance, slow drying, poor glossiness, and easy paper shrinkage. This is mainly due to the higher surface tension of water (72 dynes/cm), which makes the ink difficult to wet and dry slowly.

In order to use water-based inks in gravure printing machines, not only inks and resins require advanced technology, but also gravure printing equipment needs improvement. For example, changing an etching roller having a groove depth of about 38 μm to 42 μm into a laser plate-making drum having a groove depth of about 24 μm to 28 μm also requires more effective and powerful drying equipment and components such as rollers, pumps, and doctor blades made of corrosion-resistant materials. Because all these require a lot of investment, water-based gravure inks are still not widely available in Europe and the United States.

Ink is difficult to wet and print on substrates such as polyethylene; drying time is still the most important issue in ink applications, unless the press is equipped with enough drying equipment, or printing speed will be affected; ink gloss Less than solvent-based ink, greatly limiting the use of ink in the occasion of high gloss requirements.

Since water-based gravure inks are not yet fully capable of replacing toluene inks, the ink industry has been working hard to develop environmentally acceptable alcohol-soluble inks. Alcohol-soluble ink can help us to solve the health problems caused by toluene ink and solvent residues affect the quality of packaged foods and Other issues. In Europe and the United States, this development has become a trend. To achieve alkali resistance, ethanol resistance, water resistance, and gloss enhancement, only flexographic UV inks are used. This not only increases the printing cost, but also increases the printing process. If the beer semi-automatic production line uses an alkaline lubricant, the PH value is 9 to 10, and the water-based ink cannot withstand it. There is also summer when the South sells beer, not only to enter the refrigerator, and some are still immersed in icy water for a long time, and water-based ink cannot withstand it.

Source: 21st Century Fine Chemicals Network