For the many processes of post-press processing, most of them are carried out in the “dry†state, such as: hot stamping, embossing, die cutting, or even folding, gluing, etc., in addition to adhesives, in production No special treatment is required and no material safety issues arise. However, for UV coating, UV coating requires special treatment. At the same time, there are still some hidden dangers in the UV coating process.
Nowadays, many post-press processing factories have the capability of UV coating, and some companies are considering UV glazing as an additional service.
For companies that are applying UV glazing technology or are planning to add UV glazing services, the safety and handling of UV glazing associated with glazing processes is an important issue. This article will discuss some of the safety and operational issues in the application of UV coatings, and explain and answer some common questions.
1.UV glazing oil follows which environmental protection regulations
In the United States, many EB/UV coatings have not been defined as flammable or corrosive substances. In addition to styrene, BCEA (which contains high concentrations of flammable, corrosive olefinic acids) and EB/UV varnish diluted with flammable solvents, EB/UV curing materials are generally not environmentally friendly. "Hazardous substances" (including toxic, corrosive, flammable or reactive chemicals) as specified in the regulations. However, like all chemicals, contaminated materials and waste should also be treated.
In addition, UV/EB-cured materials contain almost no VOC (Organic Volatile Organic Compounds) and Harmful Air Contaminants (HAPS) listed by the Environmental Association. Therefore, UV/EB-cured materials are usually not listed in the public or state government's list of substances requiring attention.
2. How to deal with the by-products of the UV coating process
The only by-product of the UV lamp is ozone, a sweet, irritating gas that can be smelled at concentrations well below 0.1ppm. Regular exposure to high concentrations of ozone can lead to dry upper respiratory tract, lung allergy, and respiratory infections.
Some simple methods can avoid the operator's dangerous contact with ozone.
(1) Use a special collector to collect the emitted ozone.
(2) Fit a suitable exhaust device to the UV curing device.
(3) Use the lamp to remove ozone from the operator's side.
(4) In the work area, the cooling gas in the cooling system is not discharged outside the device, which can effectively prevent the generation of ozone. This method is safe because the high temperature gas is a very unstable substance that can quickly decompose into oxygen when passing through the exhaust passage to avoid the generation of ozone.
3. How to Dispose of Waste UV Varnish and UV Varnish
Incineration is the most feasible way to treat UV Varnish. Users of UV Varnish can find a reputable, approved company for incineration. If your company uses both traditional solvent-based coatings and UV coatings on the same equipment, both coatings can be treated with a solvent/paint waste treatment line. Solvent/paint waste is sent to the fractionation unit where the solvent is recovered and the recovered solvent can be used as a rinse or solvent wash. The solid material and precipitate after fractionation are taken to incineration.
For UV-glazed products, it was once thought that it could not be recycled. At present, the recovery of UV coating products is not difficult. In the pulp recycling process, the agitation of the paperboard in the water will separate the cellulose molecules and also separate the coating oil components. Compared with other coating methods, UV coating produces a greater proportion of hardened resin, so at present, fewer cardboards are recycled from UV polishing. However, some industry waste paper recycling companies can use these discarded UV varnish products to produce products such as sandwich boards (pads). In the recycling line, it is also possible to install a deinking separation system that allows ink and coating oil residues to precipitate and then removes these substances from the pulp.
Since the recycling of UV-coated paperboard is feasible and the current technology can completely remove the glazing contaminants in cellulose, when considering the energy consumption and solvent evaporation problems, some people in the industry are of the view that UV printing The process is more friendly to environmental protection than solvent-based or even water-based ink printing.
4. How to protect yourself when operating UV polishing equipment
UV glazing equipment should be designed to prevent UV light from reaching the operator, even when reflecting UV light, but also to minimize or prevent reflection of UV light. For safety reasons, the following protective measures are recommended when operating UV/EB polishing equipment.
(1) Wear safety glasses or take necessary measures to protect your eyes. Especially when the UV light protection measures of the UV device do not reach the optimum design, UV light filtering safety mirrors must be worn.
(2) It is best to wear nitrile rubber or butyl rubber gloves since hands are inevitably exposed to UV coating during work. The gloves of these two materials are more effective than other materials in preventing the penetration of UV coatings. If there is little chance of exposure to UV varnish, PVC (polyvinyl chloride) gloves are also a good choice in many situations. Once gloves are contaminated, clean the gloves immediately. UV latex gloves are not recommended for handling UV varnish.
(3) In the event that UV/EB polish accidentally gets onto the skin or clothes, immediately wash skin and clothes that come in contact with UV polish with neutral soap and water, or use a special cleaning agent. Then rinse the skin with warm water for 15 minutes to ensure that the UV coating on the skin is completely removed. Remember, do not use matte cleaners or solvents to clean. Because the solvent may allow more of the varnish monomer to enter the interior of the skin. After exposure to UV/EB Varnish, skin irritation generally does not occur as long as the above steps are followed immediately.
5. How to store UV Varnish
The most effective method for storing UV varnish is to place it in a black plastic container and bring it into contact with oxygen. This is because the black container can prevent sunlight from shining, and the effect of ambient light on the UV coating. Oxygen can act as an inhibitor of polymerization. Making the UV coating oil contact with oxygen in the storage process actually increases the storage life of the coating oil. There are also various containers on the market that are specifically designed for the storage of UV inks and UV coatings. In addition, storage of UV coatings should be kept away from oxidants, acids, bases, polymerization initiators, etc. It is recommended to use the recommended storage temperature for UV Varnish manufacturers to avoid overheating and overcooling.
Compared with other post-printing processes, there are many issues to consider in the UV coating process. But as long as the correct treatment is followed, the UV coating process is still a very special post-printing process. In addition, we often communicate with UV varnish suppliers and UV light curing equipment suppliers to design appropriate systems for ventilation, removal, and storage, so that the UV varnish process can be used as an additional process.
Source: "Printing Technology"