As we all know, taste and smell are chemical senses, and their stimulating effects are the result of biomolecular reactions. Scientific research shows that different positions of the tongue produce sour, sweet, bitter and salty taste effects, while the smell is more sensitive and can quickly smell subtle differences. However, it is easy for the nose to continue to work because of "fatigue". Therefore, it is usually recommended that perfume manufacturers not identify 3 or more kinds of flavors continuously. Then, how to detect the odor of packaging calendar printed matter and what is its detection standard? There is a test method used in the German calendar printing industry.
1. Gas chromatography
Gas chromatography is widely used in the production of packaging materials printed by gravure calendar. The content of residual solvent and other odors on the printed package of calendar can be determined objectively by gas chromatography. In the process of gas chromatography, the gas passes through a separation column and is measured by the detector. Even a small amount of gas can be detected. Flame ionization detector (FID) is its main detection tool. Connect the detector to PC to record the time and the amount of gas leaving the separation column. Compared with the known fluid chromatography, the free monomers can be identified. At the same time, the content of each free monomer can be obtained by measuring the recorded peak area and comparing it with the known volume. When investigating the unknown monomer of folding carton, gas chromatography and mass spectrometry (MS) are usually used to identify the unknown monomer by mass spectrometry. In gas chromatography, the headspace analysis method is usually used to analyze folding cartons. The measured sample is put into the sample vial for heating to vaporize the analyzed monomer and enter the headspace. The subsequent process is the same as the test process described above.
2. Robimson test
The Robinson test method is calibrated in the German standard dinlog55 "influence of packaging materials on the taste of test objects". For calendar printing, people are concerned about the influence of solvent residue after ink calendar printing. Therefore, calendar printing plants usually use the improved Robinson test method (mhm) to achieve the purpose of detection.
In the process of detection, the calendar is printed on the surface of the substrate with an ink amount of 1.5% m2, and then the calendar print and packaging products, such as chocolate, are rotated for a certain time (about a day) to judge the taste of the packaging. The results are usually divided into five grades: no change in the taste; 1. It is difficult to distinguish the change of taste; 2. Slight change in taste; 3. The taste has a certain change; 4. The taste has changed significantly. Sometimes, some people carry out detection under actual environmental conditions, such as putting the carton into the high temperature 75% RH for detection. The results are usually quite different from the methods specified in dinlog55.
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