What causes the peculiar smell in food packaging bags?
The peculiar smell of food packaging bags will cause food to deteriorate, even affect food quality and endanger people's health.
In particular, foods such as chocolate, milk powder, wafer biscuits and potato chips are particularly sensitive to odor requirements.
What may be the cause of the odor in the food bag?
The printing process often uses various solvents to dilute the ink in order to improve the printing adaptability of the ink, improve the transfer strength of the ink, and make the printed products more colorful, full and vivid.
After the ink is transferred to various films, the solvent in the ink will gradually evaporate;
If the surface layer of the ink is first cured, it will hinder the effective volatilization of the internal solvent, and the solvent will be completely released, that is, the solvent we belong to exceeds the standard, and the residual solvent odor will affect the packaging material.
The length of ink drying time is directly related to the startup speed.
If the starting speed of the food packaging bag exceeds the correct process requirements, the ink will solidify on the surface of the film, and the internal solvent will not be fully volatilized, especially if the last group of colors is large color blocks, the printing process should also select different kinds of inks according to the substrate selected for printing, and different solvents should be used while using different kinds of inks.
Due to the diversity of printed patterns, the pattern can be composed of monochrome blocks or multi-color blocks.
Food packaging bags, if the speed of the food packaging bags is not suitable for the early air volume and temperature in production, there will be various solvent residue problems.
Moreover, due to the different amount of glue, there are different requirements from 3G to 6g per square meter due to the heavy dry load, and the viscosity of the adhesive in production also has various requirements, if the process parameters are not set properly, the problem of excessive solvent residue is also easy to occur.
The influence of the composite process of food packaging bags 1. Select the two-component glue suitable for the ink, and the solvent also needs the requirement of composite odor, so that there is no irritating odor after the finished product.
2. The control of the amount of glue must be strictly enforced. If the amount of glue is too large or the glue layer is too thick, the solvent will not volatilize enough, resulting in excessive residual solvent.
3. The speed of the dry compound machine should be matched with the viscosity of the adhesive so that the adhesive can be fully dissolved in the solvent, and the cleanliness of the adhesive must be guaranteed without impurities, otherwise the adhesive will be uneven, it affects the volatility of the solvent, making the volatilization of the solvent in each layout inconsistent.
4. Set the temperature of each section of the oven of the dry compound machine, track the vehicle speed, set the temperature of each section, usually around 70 °c, 80 °c, 90 °c, and track and adjust the exhaust volume of each section of the oven, setting accurate exhaust air volume has completely and effectively eliminated film odor.
5, food packaging bags should be cured after compounding, curing time and temperature should be well controlled, curing time is generally 24-
28 hours, the temperature is about 45 ° C, incomplete curing will not only produce odor, but also seriously affect the peel strength.
At the same time, ensure smooth air intake and exhaust of the curing chamber.