Among the many types of labels , the most interesting one is the self-adhesive label. In the European and American label markets, self-adhesive labels dominate. In addition, the application of self-adhesive labels is also the most extensive, including food, daily chemicals, pharmaceuticals, supermarkets, electronics and other industries. Self-adhesive labels are generally divided into two categories: paper labels and film labels. The printing methods are mainly embossing, offset printing , flexo printing , etc. Therefore, when using environmentally friendly inks, it is necessary to pay attention to different printing methods.

1. Meet environmental standards

When choosing a self-adhesive label eco-friendly ink, you should first consider the industry involved in the label, such as food, pharmaceutical industry, electronics industry, or other industries, because the environmental standards of different industries are different.

China is a big manufacturing country, especially electronics production companies all over the Pearl River Delta and the Yangtze River Delta. Since most of the electronic products are products supplied globally, the environmental requirements of their packaging must meet the environmental standards of Europe and the United States, Japan and other regions and countries. As one of the main components of packaging, self-adhesive labels also need to comply with relevant environmental standards of various countries, such as FDA standards, SONY technical standards, Mattel toy standards, American toy safety standards, RoHS standards, EU food packaging printing ink guide In addition to heavy metal content control indicators, halogen content control indicators are becoming more and more important.

It should be specially pointed out that "halogen-free products" refers to the control of organic halogen compounds in electronic components. Organohalogen compounds include bromine-based substances such as PBB, PBDE, TBBP-A, HBCD, chlorine-based substances such as SCCP and alicyclic hydrocarbons, and preservatives such as PCB, PCN, and PCT, which are mainly found in plastics, plastic additives, and electronic zeros. Among the materials such as components, refrigerants, and flame retardants, these materials are prone to produce dioxin after burning, which may cause certain harm to human health.

For self-adhesive labels attached to the surface of electronic products, even if they do not affect the environment, electronic products manufacturers will still require label printing companies to use halogen-free inks for printing. The required halogen-free inks must be used. Meets the limited standard of “halogen total less than 1500 PPM, single less than 900 PPM”.

2. Correct selection of UV ink

With its wide range of printed substrate adaptability and high-performance post-processing capabilities, UV ink printing has gradually expanded from the traditional sheet-fed printing field to the web printing field, and has been widely used in label printing.

For environmentally-friendly self-adhesive labels on food, medicine, etc. (such as most food bottles in supermarkets or self-adhesive labels used on food cans, and self-adhesive labels used on medicine bottles or cans) Printing, in the choice of UV inks to avoid a misunderstanding, that is because UV ink is a solvent-free product is generally considered to be environmentally friendly products. Although UV inks do not contain volatile substances, if the photoinitiators in UV inks are not properly used, they will cause secondary pollution to foods or drugs. Therefore, it is forbidden to use photoinitiators containing benzophenone and ITX. UV ink.

At present, the Ministry of Environmental Protection does not clearly define the environmental protection technical requirements for UV inks. Even the authoritative HJ/T370-2007 "Environmental Labeling Products Technical Requirements Offset Printing Ink" will also emit radiation-curable inks (UV inks, EB inks). Excluded, label printing companies must be very careful when choosing the relevant inks.

First of all, the label printing enterprise should select the control requirements for heavy metals in accordance with HJ2503-2011 "Technical requirements for environmental labeling products, printing of the first part of lithography" and HJ/T370-2007 standards. Second, label printing companies promise not to use third parties to identify UV inks containing benzophenone and ITX photoinitiators. Finally, ink manufacturers should conduct low-odor, low-migration testing of their UV inks, especially in products where the outer packaging is a plastic bottle. At present, ink manufacturers' research on UV inks for green packaging (such as food, pharmaceuticals, packaging for daily use, etc.) is mainly focused on how to reduce the migration of harmful substances, such as the replacement of what is now commonly used with large molecular weight photoinitiators. A small molecular weight photoinitiator that meets environmental requirements in ink formulations.

3. Meet other performance requirements

In order to achieve the environmental protection of self-adhesive labels, in addition to meeting the above requirements, we should also consider the appropriate use of environmentally friendly inks from the practical use of self-adhesive labels. For example, self-adhesive labels on outdoor air conditioners need to consider performance requirements such as light fastness and rain resistance; self-adhesive labels on washing products need to consider performance requirements such as water resistance, acid and alkali resistance, and soap resistance.

In addition, when printing on synthetic paper and film self-adhesive substrates, it is also necessary to test the adhesion fastness, scratch resistance and folding resistance of the selected UV ink. This is because of the wide variety of synthetic paper and film self-adhesive substrates, and the surface treatment of the substrate is different. If the UV ink is not properly selected, the self-adhesive label made by the adhesive will cause the ink layer to fall off and fade. This will cause secondary pollution, especially for children's toy labels. Therefore, even if environmentally friendly UV inks are used, it is necessary to test the adhesion performance and other related properties before use.

The above content is selected from the " Printing Technology" of Science and Technology Media , Volume 1, 2012. For more journal content, please pay attention to the journal channel. The latest journal content is clicked into the electronic journal channel of Keyin.com.