Today’s society has developed to the extent that all goods need packaging, all packaging needs printing.Printing is the most important means of product packaging decoration processing, packaging without printing is almost unimaginable. Printing plays the role of transmitting information and publicizing products. At the same time, for some commodities, printing also plays an important role in anti-counterfeiting, today’s packaging printing is moving towards more exquisite and improve the additional value of goods.
Safety hazards of food packaging
With the increasingly fierce competition in the market today, the competition of food packaging and printing products is not only affected by the quality of the product itself, but also affected by their safety. And now packaging safety is the key problem that affects the quality of the product. How to improve the quality and safety of food and food packaging for protecting the health of consumers has become a hot spot for the government and consumers.According to the investigation, nearly 670 cities in our country have varieties of printing machines, the ink they used mainly divided into organic solvent ink, water-soluble ink, high solid ink and benzene-free ink. while the organic solvent ink uses low boiling point volatile organic compounds such as toluene, xylene, acetone, butanol and ethyl acetate to be solvents. the printing speed is fast, the printing quality is quite good and the cost is low, so it is widely used.
In the process of use, because the volatilization of organic solvents produces a large number of toxic and harmful organic waste gas,it will cause serious local pollution problem, if the human body long-term contacts with the gas ,it will bring serious harm to the nervous system and hematopoietic function. Most of the existing domestic or imported printing machines are not equipped with the corresponding purification devices when they leave the factory. If the corresponding purification device is not set up separately, there will be a large amount of toxic and harmful exhaust gas discharged directly into the atmosphere during the production process, which will seriously pollute the urban atmospheric environment and cause great harm to the urban environment and human survival.
Nowadays, printing ink is more and more widely used on the contact material, almost all food packaging can not be separated from the decoration of printing ink, but printing ink contains a large number of toxic and harmful chemicals, including: heavy metals, residual solvents, organic volatiles and polycyclic aromatic hydrocarbons. Therefore, the safety of food packaging is an essential part of food safety, and the safety of printing ink is directly related to food safety and people’s health. Especially, the food packaging based on plastic (including paper-plastic composite, aluminum-plastic composite and other composite food packaging materials) has certain moisture permeability and oxygen permeability due to its own nature,coupled with the chemical migration of printing ink, resulting in the harmful substances in printing ink on food packaging pollute the food.
Solvent residue of poor quality printing ink products such as toluene is up to 151mg/m2 (China’s requirements of food packaging for total solvent residue ≤ 10mg/m2), “soluble” lead content is up to 430mg/kg (the European Union and other developed countries for printing inks, coatings and other products “soluble” lead content limit ≤ 25mg/kg).The possible presence of harmful substances in printing inks used in food packaging depends on the type of printing inks used, the printing inks used for food packaging mainly include resin printing inks (multi-finger offset printing inks) and solvent-based printing inks .Solvent-based printing inks include benzene-soluble printing inks, alcohol-soluble printing inks, water-soluble printing inks, etc. These two types of printing inks all have safety risks such as heavy metals, soluble heavy metals, organic volatiles, solvent residues and so on.
Although our country has begun to vigorously promote the use of alcohol-soluble printing ink and water-based printing ink, because of their cost, printing process, printing speed and printing quality and other problems, solvent printing ink is still the mainstream product for food packaging in China.