The surface quality problems of the composite film ① the surface quality problems of the composite film have various forms and different causes. We think that the surface quality identification standards of the composite film should have the following three points: A. keep the ink color as far as possible after laminating. Due to the influence of aluminum plating, most of the films have different degrees of discoloration. At this time, it is necessary to see how to get as close to the original color as possible. Good ink and good glue should play their respective covering roles. B. the brightness of the surface is due to both ink and glue, so attention should be paid to identification; C. whether there are small spots. ② Analysis of the manifestation and causes of surface quality problems A. small ink spots. Generally, it is less likely to appear immediately after laminating, unless it is slag and muddy impurities. This phenomenon may occur after a period of time after coating, because of the corrosion of the ink on aluminum, when the ink presents a certain acid or alkaline, and the amount of glue is small, can not form a continuous layer, this may happen. b. Small gray point (i.e. small solid point). There are two possibilities of small gray spots, one is the uneven roller caused by glue spots, the other is the uneven ink caused by the ink is not compacted spots. Both possibilities are related to the process, which can be solved by adjusting the process, that is, increasing the thickness of the glue. c. Little white dot. General surface ink discoloration in the case of easy to appear. It often appears in the composite of aluminum coating. There are two reasons for the appearance of small white spots: first, the covering power of the ink's natural color is not strong or uneven, especially the white oil ink, which causes the aluminum color to penetrate and form small white spots where there is no aluminum color penetration; the second is the process reason, the drying channel temperature (especially the first drying channel) is too high or the amount of glue is too thick, which causes the glue layer surface condensation in the first drying channel, and ethyl ester is in the second and third drying channel When it comes out, squeeze up the glue, showing the ink color. The solution is to improve the covering power of the ink or adjust the suitable temperature for the first, second and third drying channels, and gradually increase the temperature. Avoid over temperature of the first stage. d. Small crystal point. There are two kinds of bumps and bumps on the transparent film. The causes are different: most of the protruding small crystal dots are caused by glue mixing. If the curing agent is added first and then the diluent is not followed in the correct mixing sequence (diluent first, then curing agent), the small crystal point will appear after more than ten hours. In addition, it may be because the machine has been used for a long time, but it is not Clean. The method to eliminate the small crystal point is to strictly follow the correct glue mixing method, and the machine must be cleaned after use; the concave small crystal point, carefully observed with a magnifying glass, will find that there are small bubbles, which is mainly caused by too much water. It should be noted that the water content of the diluent should not exceed 0.2%, and the unused half barrel curing agent must be covered to avoid water In. e. Little scar. Small scab refers to the point larger than the above small point, convex around the middle concave, mainly due to the uneven film activation treatment, the same scar also appears in the printing process, of course, it may also be caused by too long activation time. f. Wavy. Ripple is easy to occur on the white film, mainly because the molecular weight of the glue is not uniform. After passing through the hot drying channel and hot roller, the elastic polymer chain shrinks, and the intramolecular shrinkage of different molecular weights is not consistent. The uneven internal shrinkage causes waviness. In this case, the glue should be considered. g. The influence of film on surface quality. Due to the smoothness and uniformity of the film surface, the similar phenomena of the above six phenomena may be caused. To distinguish between the causes of the film or the above-mentioned six cases, you can carefully observe the film without lamination with a magnifying glass. Because the transparent glue is between the two films, it forms a composite film together with the two layers of film. With a magnifying glass, the spots and waves on the original small film can be enlarged. In many cases, problems can only be found by careful observation.
Dongguan Beite packaging materials Co., Ltd. - located in Dongguan City, the world's manufacturing city, is a subsidiary of Beite packaging (China) Co., Ltd., with a plant area of 6000 square meters. It is a flexible packaging enterprise integrating R & D, production and sales. It has a complete set of domestic advanced production equipment, a scientific and humanized management system and a group of experienced technical personnel For backing, to provide customers with quality products and first-class service.
The company produces composite bags, roll film, fruit bags, aluminum foil bags, suction mouth bags, self-supporting bags, zipper bags, anti-static bags, special-shaped bags, etc., which are suitable for the internal and external packaging of food, daily chemicals, electronics, toys, medicine, cosmetics, industrial products and other industries.
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