What factors will affect the transparency of Vacuum packing bags.vacuum sealer bags for food

1、 The adhesive itself is too dark in color, with deep yellow, yellow red, and sometimes even a dark red color like soy sauce soup remaining on the adhesive film. Therefore, in situations where high transparency is required, slightly yellow or even colorless high transparency adhesives should be selected.

2、 The transparency issue of the substrate. The transparency of Vacuum packing bags will be seriously affected when there are "shark skin", "runner mark", crystal point and other apparent quality problems on the surface of the inner substrate. The mist like ink stains transferred to non graphic parts during printing also significantly affect the transparency of the composite film.

3、 There are issues with the adhesive. Improper mixing procedures will result in insufficient mixing of the main agent and curing agent. Possible occurrence of "colloidal particles" phenomenon.

4、 The Vacuum packing bag has obvious appearance defects such as glue spots.

5、 Improper setting of oven temperature. At the beginning, when entering the drying channel, the temperature is too high and the drying is too fast, which causes the solvent on the surface of the adhesive layer to evaporate rapidly, causing a local increase in the concentration of the adhesive layer on the surface. As the heat penetrates into the interior of the adhesive layer, the solvent under the film vaporizes and breaks through the adhesive film, forming a circular structure like a volcanic vent. Circle by circle, it also makes the adhesive layer uneven, Also known as "orange peel like" (when viewed closely with the naked eye, it feels like the appearance of a composite film product is uneven like an orange peel, hence the name "orange peel like"), causing opacity. Therefore, the temperature of the drying channel should gradually increase from the inlet to the outlet, from low to high, with a gradient that allows the solvent to continuously evaporate from the inside to the outside in an orderly manner. In addition, when the amount of adhesive applied is too large, the adhesive layer is relatively prone to the above-mentioned defects during the drying process.

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