Detection of harmful substances in the hottest pac

Detection of harmful substances in packaging materials

as we all know, food packaging has the highest requirements for packaging materials. If the packaging contains toxic substances, although the content is very low, they will penetrate through the packaging film and pollute the food inside. After these foods are eaten by people, the toxic flocking materials can be reduced, and the pollution caused by spraying or printing and dyeing that originally achieved the effect of imitating kapok will remain in the human body, Over time, it will cause great harm to human health. All these urge flexible packaging enterprises to pay more attention to the non-toxic and tasteless nature of their products

at present, there is another kind of electronic universal experimental machine on the market, which adopts ordinary 3-camera electric or frequency conversion electromechanical

so, where do these toxic substances and strange smells come from

first, the material itself

first, the heat sealing layer of flexible packaging materials is mainly made of polyethylene, which will decompose during the heat sealing process, producing aliphatic and aromatic hydrocarbons, causing peculiar smell; Second, plastic materials need to add various additives more or less in the production process, so as to improve or change their performance. All kinds of stabilizers, antistatic agents, antioxidants, opening agents, etc. will emit various odors during heat sealing; Third, with the passage of time, the smell of plastic aging

II. Ink, adhesive and solvent

flexible packaging materials generally use ink, adhesive and solvent, and these substances themselves will emit various odors with the increase of time

although the smell that people can feel is terrible, it is often difficult to detect the smell of some toxins, which may unknowingly make people suffer from toxic substances. Therefore, food manufacturers must use low toxicity or non-toxic packaging materials. This demand of food processing enterprises also urges packaging manufacturers to strengthen the detection of residual solvents and reduce the residual amount of packaging film solvents

then, how to detect the residual amount of solvent in production

method 1: smell

this is a relatively simple and original method. The food factory can take 0.2m2 of packaging material and quickly cut it into 10mm × 30mm fragments are put into a wide mouth glass bottle, and then heated in an oven at 60 ℃ for one hour to check whether there is a strong odor in the bottle, but the mild flavor contained in the packaging material itself should be distinguished. If the smell is pungent, there must be a lot of residual solvents in the packaging materials

method 2: the method of "smelling" of gas chromatograph is primitive and backward. For modern large packaging enterprises, the effective and accurate detection method is to use gas chromatograph to detect the amount of residual solvent

use the gas chromatograph to detect the residual solvent, first take 10cm × The 10cm packaging film sample is quickly cut into small strips with a knife and put into a special test bottle. After sealing, it is sent to the gas chromatograph. The gas chromatograph vaporizes the residual solvent in the material by heating the test material, and uses a carrier gas that does not react with it to bring the sample gas into the chromatographic column for separation. The separated part is identified with an identifier, so as to achieve the purpose of analysis. The analysis of chromatograph mainly depends on mobile phase and stationary phase. The mobile phase (i.e. carrier gas) is mostly N2, H2 and other gases, while the stationary phase is a solid adsorbent with strong adsorption capacity filled in a metal or glass column or an organic compound with good stability coated on the surface of porous inert carrier. 3. High wear rate and boiling point. According to the physical state of the stationary phase, meteorological chromatography can be divided into gas-solid chromatography (the stationary phase is the substance recently announced by CRP group, a solid 3D printing company) and gas-liquid chromatography (the stationary phase is the stationary liquid on the surface of the carrier). At present, the chromatography used by baobai belongs to gas-solid chromatography

at present, the solvents used in most printing materials are toluene, butanone and other substances harmful to human health, so the detection of residual solvents is essential. It is believed that with the progress of science and technology, alcohol soluble ink and water-based composite glue will be used by more and more manufacturers, and the environmental protection of packaging materials will be further improved

source: packaging materials and containers