Since the beginning of winter, many color printing plants have encountered many quality problems due to the lamination process, such as poor peeling strength after lamination, difficulty in eliminating bubbles and increasing white spots, which have caused a lot of economic losses to enterprises. Some color printing factory's laminating workers have also said that the same dry method is used in summer, but these problems do not appear. In winter, they appear and have been unable to solve. In view of the above problems and how to control the quality of lamination in winter, the analysis and suggestions are made for Industry reference
1、 Technology of dry compound machine:
1. Tension control
(1) Unwinding and unwinding tension control system of substrate a
(2) Compound tension control system
(3) Winding tension control system
2. Drying system control:
(1) The compound machine is usually divided into three stages of drying system, the set temperature is 50-65 ℃ in the first stage, 65-75 ℃ in the second stage, and 75-80 ℃ in the third stage
(2) The wind speed should be controlled at a minimum of 25 meters per second and 35 meters per second at the outlet nozzle.
(3) Adjust the oven temperature by controlling the air volume.
3. The wire number of wire roller is related to the amount of adhesive.
4. Control the coating uniformity of scraper and adhesive.
5. Preheating system
6. Composite part
7. Cooling system
8. Winding and solidification
2、 Selection of wire roller.
1. If there is no adhesive on the machine, it is suitable for the plastic bag on the laminating machine. If the composite bag with high quality requirements is made, the reasonable selection of the gluing wire roller of the laminating machine should be carried out, and the number of lines of the wire roller should be determined, so as to control the glue loading amount and coating uniformity, and improve the product quality of the composite bag.

2. There are many kinds of wire roller, there are only two kinds used in the dry laminating machine of flexible packaging: one is the conical type, that is, pyramid type (pyramid type) and the other is truncated pyramid type (pyramid type). At present, the dry-type laminating machine used in flexible packaging basically adopts the quadripyramid type wire roller. But a certain number of wire roller, its mesh hole depth should also be in a certain range, the deeper the mesh hole, the greater the mesh capacity, the more adhesive transfer, the shorter the service life of the wire roller. Therefore, we should pay attention to the depth of the mesh hole when selecting the wire roller. Can be directly with the production of wire roller manufacturers for consultation.

3. There are basically two types of wire roller manufacturing: one is electric engraving; the other is extrusion by special equipment. In the manufacturing method, the mesh of different wire roller is also different, in the form of use is different. The scraper angle can be strictly controlled on the scraper. General manufacturers are basically using special equipment extrusion. The number of wire roller should be selected according to the quality requirements of the packaging bag.
4. Specific selection method: if making ordinary composite bag can use single component adhesive, that is, 80-120 line glue roller can be used.
Making general composite packaging bags, using two-component adhesive generally can choose 120-160 line of wire roller.
It is better to choose the wire roller with 100-120 line for the packaging bag coated with aluminum film.
3、 Preparation method of adhesive.
When winter comes, because the temperature of the workshop warehouse is very low, the temperature of the adhesive itself is also low, and the leveling property of the glue is poor. If the preparation method is carried out in summer, the dispersion will not be good. The diluent and glue will not be completely dissolved after mixing. There is always a small part of rubber particles, and the leveling property is poor. The coating effect will be affected when gluing To the occurrence of the above quality problems. Therefore, when preparing glue in winter, three steps should be taken to eliminate the existence of rubber particles: before preparing glue, it is better to put the adhesive and curing agent together at a place with high room temperature or curing room for a period of time, and then prepare and use it. When preparing, first add proper amount of ethyl ester to the adhesive and curing agent respectively, stir it gently for half an hour, then add the curing agent into the adhesive, mix it evenly and put it in the glue tank for use. In this way, the leveling property of the glue will be further improved.
4、 Equipment maintenance and operation points:
1. In winter, the cots on the laminating machine should be checked more. In general, the problems in compounding are mostly related to cots. Because of the low temperature in winter, the soft hardness of COTS changes, and the phenomenon of hardness and brittleness appears. According to the normal operation or pressure, problems may occur. According to the season, the pressure of COTS should be increased when compounding in winter. If the cots become hard or brittle, they should be replaced with new cots or grinded.
2. The temperature of drying channel is 5 ℃ - 10 ℃ higher than that in summer, and the temperature of some compound machine oven can not be raised, so the equipment factory should be contacted for transformation.
3. Control the angle of the scraper and the matching force of the wire roller to control the coating amount and coating uniformity.
4. Clean the wire roller in time and clean it when it is not in use to prevent the wire roller from blocking the net.
5、 Management of printing film and coated film
1. After printing, if the printing film cannot be compounded immediately, it is better to put it into the curing room for heat preservation (now the new curing chamber is divided into two rooms, and the two rooms are divided into constant temperature room, and the general temperature is between 30-40 ℃. It is mainly used to store pet and PA films). In this way, the printed film can keep a certain temperature, improve the leveling and dispersibility of glue, and improve the evaporation of solvent.
2. Before laminating, such as PE, PP, aluminizing, etc., should also be put into curing chamber 2 room for constant temperature, so as to improve the temperature of the film itself, increase the affinity between the two films, and avoid bubble white spots and peeling strength difference.
3. The quality of the aluminized film has a direct impact on the quality of the composite film, especially when the quality of the pet aluminum coating is poor, bubbles and white spots are easy to appear, which is the experience of many color printing factories. The same printing film for two aluminum coating composite, there are different quality.
6、 The solvent used is up to the national standard
In winter, when the compound temperature is low, the solvent used must meet the national standard. If it does not meet the requirements of the national standard, there will be other solvents or water content in the solvent exceeding the standard. If the water content of ethyl ester will affect the solubility of the glue, the dispersion will be poor. When the water molecules are baked in the oven, the water vapor can not run out and be adsorbed on the printing film. After compounding, bubbles will be produced and light myopia and white spots will appear. Therefore, the supplier must meet the national standard when using solvent in winter.
In a word, mastering the above items, together with the usual operation experience, will improve the quality of laminating film in the future, avoid the quality problems in the lamination, reduce waste and improve efficiency.
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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