Printing Ink Affecting the Safety of Liquid Food Packaging
With its advantages of convenience, environmental protection and long shelf life at room temperature, liquid food carton packaging has been favored by the majority of liquid food manufacturers and consumers. Various liquid food cartons, including Lile Bag, Camry Bag, Roof Bag and so on, have reached tens of billions of bags annually in China's production and consumption. Categories include milk, tea, fruit juice, wine and so on. Liquid food cartons, regardless of their shape and production process, have a common feature - high barrier. Its raw material is food grade base paper, which is covered with PE film or aluminium foil on the front and back of base paper by the film-spraying process to form a clean and sanitary high-barrier material. This high-barrier material is commonly called PE film paper or aluminium foil film paper, which can be used for subsequent printing methods to process various liquid foods. Carton boxes. Due to the different filling methods of each liquid food carton, there are different requirements for carton sheets, which can be divided into two categories: coil and single carton. Lile bag belongs to coil category, and roof bag belongs to single carton category. Coil category must be printed by flexographic or gravure printing, while single carton is suitable for flexographic, gravure and glue printing. Printing and other printing methods have different effects on food safety in different printing methods of liquid food cartons.
Firstly, flexographic printing is introduced. Flexographic printing is an environmentally friendly and hygienic printing method recognized internationally. Water-based ink is widely used in printing ink. Its diluent is water and ethanol. It has no harmful solvents and high safety factor. This is the way used by Lile Lippon, which accounts for the largest proportion of global sales. However, the acrylic resin, which is the main component of the traditional water-based ink, still contains trace toluene and other organic solvents. In the process of printing and back-channel film-spraying composite process, the printing ink is sealed on the paper surface by PE layer, and trace toluene and other organic solvents will remain in each carton. Lile bag must be soaked and disinfected by hydrogen peroxide before packaging liquid food. Hydrogen peroxide will be immersed into the ink layer from the side of the carton, forming a wet passage. If the subsequent sealing strip is not heat-sealed tightly and has micro-pore, the liquid food will also be immersed in the ink layer after packaging, so that part of the ink will be released to the liquid. Pollution forms in food.
Gravure printing is the most commonly used packaging production method in many domestic second and third-line liquid food (beverage) carton manufacturers in recent years. Due to the monopoly production of Lile in China, the unit price of the sheet material of Lile Bag remains high. Because of the fierce competition in the market, the manufacturers of liquid food (beverage) in the second and third lines used the original Lile Bag produced by the authentic Lile Company to pack the products, which were basically in the loss of market sales. In order to reduce the production cost, we can only replace the packaging with the Lele Pack of the domestic two or three-line liquid food (beverage) carton manufacturers. Most of these alternative packaging uses gravure printing to print with solvent ink. Due to the rapid development of ink production industry in China in recent years, a series of benzene-free alcohol-soluble gravure inks have been developed, which can be applied to printing and processing liquid food cartons. However, as with water-based ink, benzene-free alcohol-soluble gravure printing ink also has trace toluene and other organic solvents. Prints also have trace toluene and other organic solvents residues. Although the seal strip is covered by a shower film, if the heat seal of the sealing strip during the packaging process is not firm, liquid food will also be joined with printing ink. Contact forms pollution.
Therefore, we need to strictly control the production process, improve the detection system, and minimize the possibility of contamination, so as to ensure the safety of liquid food and protect the personal safety of consumers.
