Factors Affecting The Transparency Of Packaging Bags
Now the packaging bag is a kind of airtight container that is more common in our life. It has a very wide range of uses. We all know that vacuum packaging bags are generally transparent, but did you know that? In fact, it affects the packaging bag. There are many factors for transparency. Today, I will give you a good talk about the factors.
Problem With Glue
Improper compounding procedures will result in insufficient mixing of the main agent and the curing agent. May produce "gelling" phenomenon
The Adhesive Itself Is Dark In Color
The color of the adhesive itself is too dark, dark yellow, yellow-red, and sometimes even dark red like soy sauce soup, which is also the corresponding color when left on the film. Therefore, when high transparency is required, a yellowish or even colorless adhesive with high transparency should be used.
Transparency Of Substrates
When there are apparent quality problems such as "shark skin", "runner marks" and crystal points on the surface of the inner substrate, it will seriously affect the transparency of the composite product. The misty ink smudge transferred to the non-graphic part during printing also obviously affects the transparency of the composite film.
Improper Setting Of Drying Tunnel Temperature
The temperature when entering the drying tunnel is too high and the drying is too fast, so that the solvent on the surface of the glue layer evaporates rapidly, resulting in a local increase in the concentration of the glue solution on the surface layer, and the surface is crusted. When the heat penetrates into the glue layer, the film The solvent below evaporates, breaking through the adhesive film, forming a ring like a volcano vent, which also makes the adhesive layer uneven, also known as "orange peel". Therefore, the temperature of the drying tunnel should be gradually increased from the inlet to the outlet, from low to high, there is a gradient, so that the solvent can evaporate from the inside to the outside in an orderly and continuous manner. In addition, when the amount of glue applied is too large, the above-mentioned defects of the glue layer are relatively easy to occur during the drying process of the glue layer.