1, Improper selection of adhesive. The color of the adhesive itself is dark; the fluidity of the adhesive is insufficient, the flatness is poor, and it cannot be fully spread on the base film. 2, process problems.a.The inlet temperature of the drying tunnel is too high or there is no temperature gradient, the inlet temperature is too high, and the drying is too fast, so that the solvent on the surface of the glue layer evaporates rapidly, the surface is crusted, and then when the heat penetrates into the glue layer, the solvent gas under the film It breaks through the adhesive film to form a ring like a volcanic vent, and circles around it also make the adhesive layer opaque.b.The composite rubber roller or scraper is defective and cannot be pressed at a certain point, forming a neutral space and being opaque.c.There is too much dust in the ambient air, and there is dust in the hot air blown into the drying tunnel after gluing. It is stuck on the surface of the adhesive layer, sandwiched between two base films during compounding, and there are many small spots, resulting in opacity.d.The amount of glue is insufficient, there are blank spaces, and there are small air bubbles, causing mottled or opaque. Check the amount of glue to make it sufficient and uniform.e.No spreader or spreader is not clean. 3, Base material reasons. The surface tension is not high, the wettability of the glue to it is not enough, and the film is uneven after drying, which is commonly known as”hemp mask”.
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