As the saying goes: “People dress up clothes and horses to dress up saddlesâ€, and the packaging of goods has become a problem that many producers have attached importance to. With the increasing demands of people, the use of film-covering technology is widely used in outer packaging, which makes products colorful and dazzling, which greatly arouses consumers' desire to purchase. However, due to factors such as materials, process technology, equipment, and environment, the film coating process will cause factors such as blistering, wrinkling, ink removal, and peeling of the film from the environment. Wrinkle, retreat ink, peeling film from the phenomenon. Here we talk about how to avoid the development of these phenomena.
Our factory is the only manufacturer that integrates packaging and printing in the Qunbei area. It is also home to the famous Anhui Kouzi Group. It sells tens of thousands of tons of series of mouth wine every year. Its packaging is not only large in quantity but also strict in quality requirements. In the initial cover of the wine box, there were air bubbles, wrinkles, and some peeling off and Other abnormal phenomena.
After this phenomenon appeared, it immediately caught the attention of the factory's quality management personnel. After detailed analysis by technicians, the reasons are generally as follows:
1, the printed material itself Paper as a printed matter, its own nature, the performance of the ink, the density of printing graphics, etc., all affect the quality of the film. If you use a poorly-formed paper, the amount of ink absorbed in the web and the speed of absorption will not match. This will cause a change in the tightness, evenness, smoothness, and moisture content of the paper. If the printed ink layer is too thick, the adhesive molecules will have poor wetting, diffusion, and penetration. The movement of molecules between them will be relatively inactive, and the mechanical bonding force will be small. In addition, in the printing process, in order to prevent prints from becoming scumming, dry oil is often added to the ink so that the ink layer is rapidly congealed and the surface of the ink layer is crystallized. The surface of the print is smooth, tough, and loses adhesion. The adhesive cannot With its wet affinity, severely affect the bond fastness.
2. Effect of process operation and printing environment on the quality of coating film When laminating the product, firstly apply a layer of adhesive on the surface of the plastic film. After the drying treatment, the film cannot meet the requirements for film coating. In this case, the solvent is diluted to increase the concentration of the binder in order to obtain fast drying. However, if the moisture content is too high, bubbles with air are liable to appear when the film is pressurized, and then peeling off occurs. At the same time, the film easily absorbs oil, moisture, dust and other substances in the air, thereby reducing its surface function. Excessive humidity can also affect the volatilization of the solvent in the adhesive. Too much residual solvent will produce air separation in the film, making it impossible to stick the film. At the same time, uneven roller pressure, unevenness of the roller itself and dirt on the roller will cause wrinkling when the film is covered.
How to eliminate the above fault?
First, there is a bad adhesion situation 1, improper selection of adhesives, improperly set the amount of glue, ratio measurement error. The type and amount of adhesive should be reselected.
2. The diluent contains alcohol and water that consume NCO groups so that the hydroxyl groups of the main agent do not react. High-purity ethyl acetate should be used.
3, the print surface has sprayed powder. Try gently with a dry cloth.
4, the print ink layer is too thick. Should increase the amount of adhesive coating, increase the pressure.
5, printing ink layer is not dry or not completely dry. Should be hot-pressed again and then gluing; choose a high solid content of the adhesive; increase the adhesive coating thickness; increase the drying temperature and so on.
6, the adhesive is absorbed by printing ink and paper, so that the amount of coating is insufficient. Should be re-formulated and set the amount of coating.
7, plastic film surface treatment is not enough or beyond the application period, so that the treatment surface failure. Plastic film should be replaced.
8, the pressure is too small, the speed is faster, the temperature is low. The film temperature and pressure should be increased and the vehicle speed should be appropriately reduced.
Second, there is a phenomenon of blistering, printing ink layer is not dry. Should be hot pressed again and then glue; delay filming time, make it completely dry.
2, the printing ink layer is too thick. The amount of adhesive applied should be increased to increase the pressure and the composite temperature.
3, drying temperature is too high, the adhesive surface crust. Drying temperature should be reduced.
4, the surface temperature of the composite roller is too high. The composite roll temperature should be reduced.
5, thin touch with wrinkles or relaxation phenomena, uneven film or curling. Replace the film and adjust the tension.
6, dust and impurities on the surface of the film. Should be promptly removed.
7, uneven adhesive coating, the amount of less. Should increase the amount of coating and uniformity.
8, the binder concentration is too high, viscosity, uneven coating. Apply thinner to reduce the binder concentration.
Third, film wrinkling 1, film transfer roller imbalance. Should adjust the delivery stick.
2. Inconsistent or undulating edges of the film at both ends. Replace qualified film.
3, the glue layer is too thick, the solvent evaporation is not thorough, affecting the viscosity, squeezed by the pressure roller, the paper and the film slide. The amount of glue should be adjusted to increase the temperature of the drying tunnel.
4, the electric roller and the rubber roller are not balanced at both ends, the pressure is inconsistent, and the line speed is not equal. Two rollers should be adjusted. (Wang Hao)
Our factory is the only manufacturer that integrates packaging and printing in the Qunbei area. It is also home to the famous Anhui Kouzi Group. It sells tens of thousands of tons of series of mouth wine every year. Its packaging is not only large in quantity but also strict in quality requirements. In the initial cover of the wine box, there were air bubbles, wrinkles, and some peeling off and Other abnormal phenomena.
After this phenomenon appeared, it immediately caught the attention of the factory's quality management personnel. After detailed analysis by technicians, the reasons are generally as follows:
1, the printed material itself Paper as a printed matter, its own nature, the performance of the ink, the density of printing graphics, etc., all affect the quality of the film. If you use a poorly-formed paper, the amount of ink absorbed in the web and the speed of absorption will not match. This will cause a change in the tightness, evenness, smoothness, and moisture content of the paper. If the printed ink layer is too thick, the adhesive molecules will have poor wetting, diffusion, and penetration. The movement of molecules between them will be relatively inactive, and the mechanical bonding force will be small. In addition, in the printing process, in order to prevent prints from becoming scumming, dry oil is often added to the ink so that the ink layer is rapidly congealed and the surface of the ink layer is crystallized. The surface of the print is smooth, tough, and loses adhesion. The adhesive cannot With its wet affinity, severely affect the bond fastness.
2. Effect of process operation and printing environment on the quality of coating film When laminating the product, firstly apply a layer of adhesive on the surface of the plastic film. After the drying treatment, the film cannot meet the requirements for film coating. In this case, the solvent is diluted to increase the concentration of the binder in order to obtain fast drying. However, if the moisture content is too high, bubbles with air are liable to appear when the film is pressurized, and then peeling off occurs. At the same time, the film easily absorbs oil, moisture, dust and other substances in the air, thereby reducing its surface function. Excessive humidity can also affect the volatilization of the solvent in the adhesive. Too much residual solvent will produce air separation in the film, making it impossible to stick the film. At the same time, uneven roller pressure, unevenness of the roller itself and dirt on the roller will cause wrinkling when the film is covered.
How to eliminate the above fault?
First, there is a bad adhesion situation 1, improper selection of adhesives, improperly set the amount of glue, ratio measurement error. The type and amount of adhesive should be reselected.
2. The diluent contains alcohol and water that consume NCO groups so that the hydroxyl groups of the main agent do not react. High-purity ethyl acetate should be used.
3, the print surface has sprayed powder. Try gently with a dry cloth.
4, the print ink layer is too thick. Should increase the amount of adhesive coating, increase the pressure.
5, printing ink layer is not dry or not completely dry. Should be hot-pressed again and then gluing; choose a high solid content of the adhesive; increase the adhesive coating thickness; increase the drying temperature and so on.
6, the adhesive is absorbed by printing ink and paper, so that the amount of coating is insufficient. Should be re-formulated and set the amount of coating.
7, plastic film surface treatment is not enough or beyond the application period, so that the treatment surface failure. Plastic film should be replaced.
8, the pressure is too small, the speed is faster, the temperature is low. The film temperature and pressure should be increased and the vehicle speed should be appropriately reduced.
Second, there is a phenomenon of blistering, printing ink layer is not dry. Should be hot pressed again and then glue; delay filming time, make it completely dry.
2, the printing ink layer is too thick. The amount of adhesive applied should be increased to increase the pressure and the composite temperature.
3, drying temperature is too high, the adhesive surface crust. Drying temperature should be reduced.
4, the surface temperature of the composite roller is too high. The composite roll temperature should be reduced.
5, thin touch with wrinkles or relaxation phenomena, uneven film or curling. Replace the film and adjust the tension.
6, dust and impurities on the surface of the film. Should be promptly removed.
7, uneven adhesive coating, the amount of less. Should increase the amount of coating and uniformity.
8, the binder concentration is too high, viscosity, uneven coating. Apply thinner to reduce the binder concentration.
Third, film wrinkling 1, film transfer roller imbalance. Should adjust the delivery stick.
2. Inconsistent or undulating edges of the film at both ends. Replace qualified film.
3, the glue layer is too thick, the solvent evaporation is not thorough, affecting the viscosity, squeezed by the pressure roller, the paper and the film slide. The amount of glue should be adjusted to increase the temperature of the drying tunnel.
4, the electric roller and the rubber roller are not balanced at both ends, the pressure is inconsistent, and the line speed is not equal. Two rollers should be adjusted. (Wang Hao)
Apache Industry Ltd. , http://www.apachedisplay.com