The peculiar smell of packaging bag
s not only affects the contents of the packaging, but also harms the health of customers to a certain extent, which is a problem that cannot be ignored in product safety. How to reduce the odor of composite packaging bags
has become a basic requirement of the packaging bag industry. Next, professional flexible packaging manufacturers will combine their rich experience in the production of composite packaging bags to interpret the causes and solutions of peculiar smells in packaging bags. 1. The source of peculiar smellThe peculiar smell in the film mainly comes from two parts: various additives of the resin itself and its own low molecular substances; the peculiar smell in flexible packaging processing. Films, various inks, adhesives, and organic solvents all bring various odors. The odors produced by packaging materials are of various types, complex and changeable, including sweet, sour, sulfur, medicinal, burnt, paraffin, petroleum, ink, soap, tar, solvent, and so on. Odors are not only caused by a single substance, but are often caused by a mixture of several substances. Even describing odors is particularly difficult, because small changes in the composition of the mixture can lead to differences in odor. 2. Source analysis 1. Influence of resin itself Films are generally processed with polymer resins. The resins are composed of molecules of different sizes, and the molecular weight distribution of different resins is different, and the content of low molecules is also different. Low-molecular-weight substances are easily oxidized and volatilized during extrusion, resulting in odor. The resin synthesis process is divided into solution method and meteorological method. The two different composition methods also have different odors: the solution method has many low-molecular substances removed by the process of removing the solution after the composition, so the taste is theoretical. It is better than the meteorological method. Many additives are added to the resin to improve performance, and these additives are the largest source of taste. Slipperants are generally amide compounds with some sweet taste. Antistatic agents have a very strong smell and should not be used in low-odor packaging. The opening agent is generally based on inorganic substances, usually calcium carbonate and silicon dioxide. However, in terms of opening effect, silica is far better than calcium carbonate, but in terms of taste, calcium carbonate is better than silica. Antioxidants are usually phenolic things that also have a certain taste. Generally linear molecules have the problem of catalyst residues, so it is necessary to add antioxidants. Color masterbatch: Commonly used white masterbatches are generally added with some waxes and stearate as dispersants and lubricants. These low-molecular-weight substances will be separated during processing and have a great taste, so they should be placed in the middle layer as much as possible in multi-layer co-extrusion. 2. The peculiar smell in the production process of the composite packaging bag 1. Thermal decomposition produces polyethylene decomposition to produce peculiar smell, which can be roughly divided into two categories: aliphatic hydrocarbons and aromatic hydrocarbons. According to the research, thermal decomposition into saturated or unsaturated hydrocarbons of three carbons to twenty-eight carbons, among which the three to six carbon compounds produced by short chain branches, have the greatest impact on the content, due to the low volatility and polarity. Not high, these substances can be preserved in the membrane for a long time. 2. Thermal oxidation produces peculiar smell When plastic is processed under high temperature and high shear force, in addition to thermal decomposition, after extrusion of the die mouth, it will also have thermal oxidation reaction with oxygen in the air, and the generated substances will also cause peculiar smell. Surface corona treatment produces peculiar smell In order to make the ink or adhesive have better viscosity, it is necessary to corona or flame treatment of different plastic films. As the surface tension of the offset plate becomes stronger due to the oxidation reaction, a group of substances (hydroxyl, aldehyde, ketone and carboxyl) generated during processing will be encountered in the subsequent application of the coating. Assuming that the increased intensity of the treatment will not only increase the surface tension, but will also degrade the polymer to a greater extent, and then produce small transpirable molecules (aldehydes and ketones); these transpirable aldehydes and ketones contribute to off-flavors . 3. Odor generated during heat sealing When the composite film is heat-sealed at high temperature, the material will separate out the thermal decomposition increasing agent, and various components in the ink adhesive will evaporate and decompose to produce odor. Odor produced by plastic additives During the processing and molding process of plastics, in order to improve the processability or improve the function of the product, various additives will be added. Such as plasticizers, heat stabilizers, antioxidants, anti-ultraviolet agents, lubricants, blocking agents, antistatic agents, antifogging agents, etc.; other inorganic additives that will increase functionality, such as calcium carbonate, kaolin, Talc, silicon oxide, etc., will bring in a lot of dispersants, coupling agents, etc.; in addition, various organic pigment masterbatches, titanium white masterbatches, etc. will be added, which will produce many transpiration substances when heated. Materials, etc., can promote polymer differentiation, and severe odor will occur during heat sealing.
Additionally, Qingdao Supouches Packaging Ltd. has a few new features planned to roll out in the app to provide more convenience, comfort and options to our clients.
Qingdao Supouches Packaging Ltd. is one of leading flexible packaging solutions
flexible packaging distributors. You can order , and accessories for your need. Meeting your business need is always our top priority. Any of your enquiry is warmly welcomed.
Once we have a good idea of how flexible packaging can satisfy customer’s needs, consider whether we should create a skill for their demands.