The Method and Necessity of Testing Residual Solvent for Compound Packaging Materials

[Chinese Packaging News] The safety of high-polymer materials used in food packaging has always been a controversial focus. The topics of debate in the past have often centered around whether high-polymer materials would create harmful free forms during use. In recent years, due to the continuous emergence of excessive amounts of residual solvents on the packaging bags, the safety of the use of high-polymer bags has once again received widespread attention. With the mandatory implementation of food packaging 3C certification, the detection of solvent residues in polymer materials is no longer an option.

Composite materials are commonly used packaging materials and are widely used in food, medicine, beverages and other fields. It integrates the excellent properties of a variety of polymer materials, which can effectively extend the product's shelf life. The solvent residue of the composite package is generally generated in the ink, solvent, and production process. The quality of the ink, the drying speed of the dilution solvent, the performance of the machine, the environment, and the packaging structure all affect the residual amount of the solvent. At present, the domestic packaging color printing industry mainly uses organic inks. High-temperature drying is the main organic solvent removal method, but the inks contain different amounts of solvents such as toluene, butanone, and ethyl esters, which have different volatilization rates. Caused a variety of solvent residues in different values. When the residual amount of solvent exceeds a certain limit, it will cause contamination of the contents of the package, which in turn will cause harm to the health of consumers. The solvent residue detection of composite packaging materials is generally performed after printing. The testing method and standards are as stipulated in the 2006 National Standard for Production of Food Packaging, Containers, and Tools, etc., and the total amount of residual solvents for packaging food should be ≤10 mg/ M2, where the residual amount of benzene solvent is ≤ 3 mg/m2.

The residual solvent usually contained in the package mainly contains toluene, xylene, butanone, isopropanol, butyl acetate, ethyl acetate, etc., depending on the specific materials used and the ink. For flexible packaging plants, there are many factors that cause excessive solvent residues, such as improper selection of substrates, non-standard production processes, aging of equipment, and lack of necessary inspection and control at all stages of production. In addition, soft packaging production equipment if there is a drying tunnel heating temperature is not appropriate, the amount of drying air is not uniform, uneven coating coating, production speed is not reasonable and other phenomena will cause the solvent residue of the compound packaging exceeded. In fact, it is necessary to carry out solvent residue detection for raw materials and finished products. The flexible packaging plant can adjust production raw materials and processes accordingly to effectively improve the quality of products based on the actual test results.

Residual detection equipment. The specially configured gas chromatography workstation (software) can not only directly detect the names of various types of residual solvents in the composite package, but also can directly display the residual content (mg/m2) of such solvents, facilitating the test personnel to refer to the testing standards for data. Analysis, in addition, the purity of the solvent used can also be detected. The GC-9860 gas chromatograph developed by Shandong Tengzhou Luchuang Analytical Instrument Co., Ltd. (which can also be equipped with a headspace sampler) can be detected in only 13 minutes. The test process does not require a program to heat up, because most programs will heat up. Baseline drift causes errors in the test analysis. In principle, it is not possible to use a program to heat up without using a program, unless there is a need for multicomponent separation detection. The entire testing process is mainly divided into gas chromatograph preheating, sample preparation, baking, sampling gas, injection into the gas chromatograph, and obtaining test results. The company can provide analytical method establishment, data testing, personnel training and other services for the control of solvent residues in packaging materials.

Nowadays, with the advancement of science and technology, the development and use of benzene-free inks, water-based inks, and various types of environmentally friendly adhesives have brought bright prospects for the complete resolution of solvent residue problems in composite packaging, but currently due to price factors and The replacement of existing equipment and other issues have limited their widespread use. Now, the composite package must be able to reach the standard for solvent residue. When using the gas chromatograph, it must also be improved by improving the existing manufacturing process and strengthening the detection mechanism.