China has introduced lamination technology and technology for more than ten years. The quality of lamination film has not been stable. It is still in the discussion stage. There are no substantial breakthroughs in some key technologies, processes, raw materials, etc. Many units still use the early "wet" compound technology. This kind of technology has many drawbacks, such as the large plasticity of the process operation, the quality of the adhesive itself, the environmental pollution, the harm to the human body, and the problems such as “super-crease and blistering†of the composite parts.
For this reason, since 1994, the domestic printing industry has carried out research on laminated film quality for several years. Concerned with the lamination technology, process, raw materials and other issues to obtain a consistent view, and the overall promotion of the use of pre-coating film, to fully switch to the domestic pre-coating film, focusing on the domestic pre-coating film composite process, technology made some adaptable discussion. The following is a brief discussion on the composite technology of domestic pre-coated films.
First, the basic principle of laminating film The principle of paper-plastic laminating of laminating film looks simple on the surface, one can see and understand, one or two days can operate independently, in fact, many operators often do not understand the principle of paper-plastic composite technology. Can not accurately grasp the specific relationship between temperature, speed, and pressure in the specific operations. Therefore, the product quality stability is not good, there are "bubbling, filming" products from time to time.
Paper-plastic compound usually refers to the bonding of paper (print) and BOPP film. After the BOPP film is glued, it is dried, dried, re-wound, and slit into strips. When the paper-plastic composite is used, the precoating film melts the solid adhesive layer under the action of the surface temperature of the hot-pressing cylinder, and the adhesive layer becomes a fluid body. The adhesive fluid quickly wets and penetrates the surface of the print, and then the adhesive cools and the adhesive solidifies. . The adhesive particles penetrating into the surface of the print, like "nails", secure the film to the print, resulting in a strong adhesive interface layer, and a paper-plastic composite is born. This process is instantaneous and complete. Because the hot roller and the rubber roller are round-circular, the contact point forms a line, so it is called "line pressure". Since the melting of the adhesive layer and the paper-plastic lamination are all performed under the action of the on-line pressure, the quality of the composite product is determined at this moment.
Second, the impact of temperature on the quality of paper and plastic composites 1. The best composite temperature We use the pre-coated film are hot-melt type. The glue melts at a certain temperature. Each pre-coated product must provide the user with compound parameters. It can be seen that the compound temperature is established and very important. Composite temperature refers to the temperature required to completely melt the adhesive layer. The melting temperature is called "melting point." The "melting point" is not the boiling point of 100°C, which is well-known under boiling water boiling at normal pressure. The precoat film is composed of a variety of macromolecules. Due to the different molecular structures of the polymer materials and the different molecular weights, the “melting point†of the adhesive layer cannot be fixed at a temperature “pointâ€. Under the effect of heat, the adhesive layer undergoes a process of change from softening to completely "melting" the fluid. We call this process a "melting range." For example, some pre-film manufacturers offer a compounding temperature of 80°C. Some glue in the adhesive layer may have melted at a temperature of 70°C or even lower, and some of them will begin to soften, and must reach a temperature of 80°C. The adhesive layer melts completely at °C. At this time, the adhesive layer can be changed from a solid state to a liquid state with fluidity. In this state, only the wetting and penetration ability can be achieved. At this time, the adhesive ability of the adhesive can be fully generated, and the adhesiveness of the composite product can be maximized.
2. How to select and determine the best compound temperature How to select and determine the best compound temperature is the first condition for obtaining a high-quality composite product. As a user of the precoat film, when we select the best compounding temperature, we must consider two issues separately: First, the compound temperature provided by the manufacturer can be regarded as a reference value, and must be verified in specific applications; second is to consider The sensitivity of the temperature "probe" to the temperature of the laminator used, as well as the actual temperature difference reflected on the thermostat. Since the optimal reheating temperature is not an intuitively visible figure, the quality of the composites at different temperatures under normal speed and pressure is analyzed and judged, and the composite temperature we need is selected.
(1) The composite product at the best re-use temperature has a high surface gloss, brightness, transparency, and vivid colors. The color of the image and text is thicker and fuller than the compound color. Black is darker and red is redder. Blue is bluer. Composite parts are not curled or warped. If the composite exhibits the above or near the above level, it can be determined as the optimal composite temperature required.
(2) Composites produced below the optimal compounding temperature must have poor gloss, low brightness, and low transparency. Images and text are gray, imaginary, floral, dark and old. In severe cases, it seems that there is an isolation layer between the print and the film, which is caused by incomplete melting of the adhesive layer. This kind of composite piece is to "fold" the film, that is, there is a white fold, which is a precursor to "film stripping" and "bubbling". If it is the cover of a textbook, when bound into a book, as long as you flip it a few times, it will “blister†or even “releaseâ€. That is because the compounding temperature is low, although part of the glue in the glue layer has melted, but a part of the glue only softens, and it is difficult for the naked eye to observe. The colloidal fluidity of this kind is poor, the wetting ability is low, the adhesive force cannot be produced at all, the composite printed part is false sticky, the semi-adhesive half between the film and the printed part, the peeling force is low, this paper and film can be easily separated. And the film surface is not muddy. This composite is still a good product as long as it is reheated again. At the time of starting up, it is very easy to produce this kind of product while warming up and trimming. Pay special attention.
(3) The latitude is higher than the optimal compounding temperature or the composite temperature provided by the manufacturer, that is, the above mentioned "melting range" is too long, which will cause the glue liquid to cool and solidify longer. If the composite member is separated from the pressure, the glue of the adhesive between the printing member and the film cannot be cured within a certain period of time to fix the paper film. During film rewinding, the stretching effect of the film will reduce the adhesion effect. If the winding is loose at this time, the problem described in (2) may also occur. At this time, some temperatures may be appropriately lowered or the compounding speed may be slowed down, and some adjustments may be made from the process, so as to obtain better products. However, it should be noted that if the adjustment is improper, there may be warping of the composite parts.
Third, the impact of speed, pressure on the quality of composite parts The new laminating machine rubber roller turns flat, the pressure is generally set at 100kg/cm2. After the long-term operation of the old equipment, the rubber roller may be deformed due to the effect of heat and pressure, showing an ellipse or bump, and the pressure may be properly adjusted to 150-180 kg/cm2, which can meet the requirements for compounding. At this time, the speed of compounding must be properly regulated. The three are mutually reinforcing and indispensable. In order to pursue production and speed up compounding, this is the most common quality accident in daily compound operations. The reason is that the contact time between the adhesive layer and the hot roller is too short, and the adhesive layer cannot be completely melted. Of course, if the printed product is a product with a small number of texts and images and mostly blanks, it is appropriate to increase some speeds when compounding, and it is still possible to increase the temperature accordingly. However, full version, field version, multi-color printing plate must not be used, then we must standardize the operation.
Fourth, the best composite temperature, speed selection method The best choice of compound temperature, speed selection method is more convenient, but also very simple, can be done at any time in daily production, and can quickly come to a conclusion.
1. Compounding with the compound temperature provided by the manufacturer and compounding speed in daily production. If the quality of the composite reaches or approaches the quality level described in point (1), it can be considered as the best combination of speed and temperature.
2. If the quality of the composite product is as described in (2), it may be due to a high speed or a low temperature. At this point, as long as the composite temperature is kept unchanged, the composite speed is gradually reduced, and each "speed" composite product is compared to reach the quality of the composite product as described in point (1), indicating that the "speed" and the temperature are the most Good match.
3. Change the speed and still fail to meet the quality requirements. At this time, the speed can be kept constant, and the temperature can be increased step by step to compare the "segment temperature" composite products to reach or approach the quality of (1) point). It can also be seen that "segment temperature" and speed are the best match.
5. After the test method of composite parts adopts pre-film coating compounding, the plasticity of the process operation is greatly reduced, and many objective and unfavorable factors are also disappeared, which facilitates on-site management and simplifies the inspection method. According to the usual experience, the test method can be summed up in three words: look, fold, and twist.
See: Observe whether the gloss, brightness, transparency, and color of the composite are as described in point (1). If the quality level described in point (1) is reached, it indicates that the selection of temperature, speed, and pressure is correct, the process is reasonable, and the operation specification.
Folding: On the basis of watching, the composite film is folded face to face, and if there is no white folded, it basically achieves the bonding effect. If white folds appear, there may be problems with the intrinsic quality of the precoat film.
æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“. The “no blistering, no strippingâ€, or the separation of the paper film, the paper on the film surface, and the damage of the surface of the prints indicate that the pre-coated film is of good quality and the compounding process is reasonable and standardized. On the contrary, it can be concluded that the precoat has quality problems. Domestic pre-coated films are not very ideal in the full version, field version, multi-color overprinted parts composite, and sometimes it is difficult to escape the "æ“".
Some domestic pre-coated membranes have poor dry surfaces and their hands are sticky. They are not suitable for viewing, folding or boring. Color insertion tests can also be used to determine the quality of pre-coated membranes. The color insertion test method is: take a stack of positive and negative eight-color offset paper prints, put the composite pieces into them, set for 24 hours, observe whether the composite parts "wrinkle." Such as "wrinkle" can determine the solvent resistance of the ink layer of the ink layer is weak, adaptability, there must be selective use, otherwise it shows that the pre-coating film adaptability is good, can be boldly used in the standard operation of a variety of printing composite.
The above-mentioned empirical test methods, though not scientific, are simple and intuitive and easy to grasp. As a means and method of management, it is convenient for self-inspection and mutual inspection of machine operators, and problems can be detected in a timely manner to avoid the appearance of defective quality products, which has a certain positive effect.
Sixth, the need for standardized operation At present, domestic pre-coated film still has many shortcomings, but compared with the "wet" compound, the composite quality is relatively stable. As the reform of old composite technologies and processes, the quality of stable composite products is also a direction. However, there are still many things to be done to stabilize the composite quality of domestic pre-coated films. Pre-coated film manufacturers should study how to improve their own quality, and users should continue to discuss the composite process. For correct and reasonable processes, we must emphasize the importance of standardized operations. Using standard operating techniques to make up for certain congenital deficiencies, give full play to the latent adaptability of the pre-coated film, so as to achieve better results, but also conducive to the accurate analysis, determination of quality accidents and take effective measures.
VII. Views and Requirements on Domestic Pre-coated Films 1. The pre-coating film is pollution-free, eliminating “wet†compound environmental pollution, harm to the human body and fire hazards, is a major step forward.
2. The use of pre-coating film simplifies the process operation, reduces the labor intensity of workers, eliminates many unfavorable factors of "wet method" combined with objective and man-made, and provides favorable conditions for improving the quality level of composites. It is a new process for paper-plastic composites. The application of technology clearly defines the direction.
3. The domestic pre-coating film production has just started, is still unstable, poor adaptability, and has certain limitations. In particular, weak solvent resistance, and low wettability and penetration of low-interfacial layers formed by multi-color overprinting are the key to the difficulty of the promotion of domestic pre-coated films. Pre-coated film producers should make necessary screening for material selection and structure of the adhesive layer.
4 uneven coating, poor rewinding, coating thicker, coating thickness, thin inconsistent, rewind loose, tight edges, wrinkles is also a major drawback.
5. It is imperative to improve the quality of the pre-coated adhesive layer and improve the adaptability to various types of prints as soon as possible. Reducing the specific gravity of the precoating film is also one of the directions for improving the quality of the precoating film.
The use of pre-coated membranes has changed the state of stagnation in China's lamination process and technology for more than ten years, and has taken a new approach to improving the quality of lamination in China. However, at present, there are many problems in the production of pre-coating films in the country, and the printing industry is still not
For this reason, since 1994, the domestic printing industry has carried out research on laminated film quality for several years. Concerned with the lamination technology, process, raw materials and other issues to obtain a consistent view, and the overall promotion of the use of pre-coating film, to fully switch to the domestic pre-coating film, focusing on the domestic pre-coating film composite process, technology made some adaptable discussion. The following is a brief discussion on the composite technology of domestic pre-coated films.
First, the basic principle of laminating film The principle of paper-plastic laminating of laminating film looks simple on the surface, one can see and understand, one or two days can operate independently, in fact, many operators often do not understand the principle of paper-plastic composite technology. Can not accurately grasp the specific relationship between temperature, speed, and pressure in the specific operations. Therefore, the product quality stability is not good, there are "bubbling, filming" products from time to time.
Paper-plastic compound usually refers to the bonding of paper (print) and BOPP film. After the BOPP film is glued, it is dried, dried, re-wound, and slit into strips. When the paper-plastic composite is used, the precoating film melts the solid adhesive layer under the action of the surface temperature of the hot-pressing cylinder, and the adhesive layer becomes a fluid body. The adhesive fluid quickly wets and penetrates the surface of the print, and then the adhesive cools and the adhesive solidifies. . The adhesive particles penetrating into the surface of the print, like "nails", secure the film to the print, resulting in a strong adhesive interface layer, and a paper-plastic composite is born. This process is instantaneous and complete. Because the hot roller and the rubber roller are round-circular, the contact point forms a line, so it is called "line pressure". Since the melting of the adhesive layer and the paper-plastic lamination are all performed under the action of the on-line pressure, the quality of the composite product is determined at this moment.
Second, the impact of temperature on the quality of paper and plastic composites 1. The best composite temperature We use the pre-coated film are hot-melt type. The glue melts at a certain temperature. Each pre-coated product must provide the user with compound parameters. It can be seen that the compound temperature is established and very important. Composite temperature refers to the temperature required to completely melt the adhesive layer. The melting temperature is called "melting point." The "melting point" is not the boiling point of 100°C, which is well-known under boiling water boiling at normal pressure. The precoat film is composed of a variety of macromolecules. Due to the different molecular structures of the polymer materials and the different molecular weights, the “melting point†of the adhesive layer cannot be fixed at a temperature “pointâ€. Under the effect of heat, the adhesive layer undergoes a process of change from softening to completely "melting" the fluid. We call this process a "melting range." For example, some pre-film manufacturers offer a compounding temperature of 80°C. Some glue in the adhesive layer may have melted at a temperature of 70°C or even lower, and some of them will begin to soften, and must reach a temperature of 80°C. The adhesive layer melts completely at °C. At this time, the adhesive layer can be changed from a solid state to a liquid state with fluidity. In this state, only the wetting and penetration ability can be achieved. At this time, the adhesive ability of the adhesive can be fully generated, and the adhesiveness of the composite product can be maximized.
2. How to select and determine the best compound temperature How to select and determine the best compound temperature is the first condition for obtaining a high-quality composite product. As a user of the precoat film, when we select the best compounding temperature, we must consider two issues separately: First, the compound temperature provided by the manufacturer can be regarded as a reference value, and must be verified in specific applications; second is to consider The sensitivity of the temperature "probe" to the temperature of the laminator used, as well as the actual temperature difference reflected on the thermostat. Since the optimal reheating temperature is not an intuitively visible figure, the quality of the composites at different temperatures under normal speed and pressure is analyzed and judged, and the composite temperature we need is selected.
(1) The composite product at the best re-use temperature has a high surface gloss, brightness, transparency, and vivid colors. The color of the image and text is thicker and fuller than the compound color. Black is darker and red is redder. Blue is bluer. Composite parts are not curled or warped. If the composite exhibits the above or near the above level, it can be determined as the optimal composite temperature required.
(2) Composites produced below the optimal compounding temperature must have poor gloss, low brightness, and low transparency. Images and text are gray, imaginary, floral, dark and old. In severe cases, it seems that there is an isolation layer between the print and the film, which is caused by incomplete melting of the adhesive layer. This kind of composite piece is to "fold" the film, that is, there is a white fold, which is a precursor to "film stripping" and "bubbling". If it is the cover of a textbook, when bound into a book, as long as you flip it a few times, it will “blister†or even “releaseâ€. That is because the compounding temperature is low, although part of the glue in the glue layer has melted, but a part of the glue only softens, and it is difficult for the naked eye to observe. The colloidal fluidity of this kind is poor, the wetting ability is low, the adhesive force cannot be produced at all, the composite printed part is false sticky, the semi-adhesive half between the film and the printed part, the peeling force is low, this paper and film can be easily separated. And the film surface is not muddy. This composite is still a good product as long as it is reheated again. At the time of starting up, it is very easy to produce this kind of product while warming up and trimming. Pay special attention.
(3) The latitude is higher than the optimal compounding temperature or the composite temperature provided by the manufacturer, that is, the above mentioned "melting range" is too long, which will cause the glue liquid to cool and solidify longer. If the composite member is separated from the pressure, the glue of the adhesive between the printing member and the film cannot be cured within a certain period of time to fix the paper film. During film rewinding, the stretching effect of the film will reduce the adhesion effect. If the winding is loose at this time, the problem described in (2) may also occur. At this time, some temperatures may be appropriately lowered or the compounding speed may be slowed down, and some adjustments may be made from the process, so as to obtain better products. However, it should be noted that if the adjustment is improper, there may be warping of the composite parts.
Third, the impact of speed, pressure on the quality of composite parts The new laminating machine rubber roller turns flat, the pressure is generally set at 100kg/cm2. After the long-term operation of the old equipment, the rubber roller may be deformed due to the effect of heat and pressure, showing an ellipse or bump, and the pressure may be properly adjusted to 150-180 kg/cm2, which can meet the requirements for compounding. At this time, the speed of compounding must be properly regulated. The three are mutually reinforcing and indispensable. In order to pursue production and speed up compounding, this is the most common quality accident in daily compound operations. The reason is that the contact time between the adhesive layer and the hot roller is too short, and the adhesive layer cannot be completely melted. Of course, if the printed product is a product with a small number of texts and images and mostly blanks, it is appropriate to increase some speeds when compounding, and it is still possible to increase the temperature accordingly. However, full version, field version, multi-color printing plate must not be used, then we must standardize the operation.
Fourth, the best composite temperature, speed selection method The best choice of compound temperature, speed selection method is more convenient, but also very simple, can be done at any time in daily production, and can quickly come to a conclusion.
1. Compounding with the compound temperature provided by the manufacturer and compounding speed in daily production. If the quality of the composite reaches or approaches the quality level described in point (1), it can be considered as the best combination of speed and temperature.
2. If the quality of the composite product is as described in (2), it may be due to a high speed or a low temperature. At this point, as long as the composite temperature is kept unchanged, the composite speed is gradually reduced, and each "speed" composite product is compared to reach the quality of the composite product as described in point (1), indicating that the "speed" and the temperature are the most Good match.
3. Change the speed and still fail to meet the quality requirements. At this time, the speed can be kept constant, and the temperature can be increased step by step to compare the "segment temperature" composite products to reach or approach the quality of (1) point). It can also be seen that "segment temperature" and speed are the best match.
5. After the test method of composite parts adopts pre-film coating compounding, the plasticity of the process operation is greatly reduced, and many objective and unfavorable factors are also disappeared, which facilitates on-site management and simplifies the inspection method. According to the usual experience, the test method can be summed up in three words: look, fold, and twist.
See: Observe whether the gloss, brightness, transparency, and color of the composite are as described in point (1). If the quality level described in point (1) is reached, it indicates that the selection of temperature, speed, and pressure is correct, the process is reasonable, and the operation specification.
Folding: On the basis of watching, the composite film is folded face to face, and if there is no white folded, it basically achieves the bonding effect. If white folds appear, there may be problems with the intrinsic quality of the precoat film.
æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“ æ“. The “no blistering, no strippingâ€, or the separation of the paper film, the paper on the film surface, and the damage of the surface of the prints indicate that the pre-coated film is of good quality and the compounding process is reasonable and standardized. On the contrary, it can be concluded that the precoat has quality problems. Domestic pre-coated films are not very ideal in the full version, field version, multi-color overprinted parts composite, and sometimes it is difficult to escape the "æ“".
Some domestic pre-coated membranes have poor dry surfaces and their hands are sticky. They are not suitable for viewing, folding or boring. Color insertion tests can also be used to determine the quality of pre-coated membranes. The color insertion test method is: take a stack of positive and negative eight-color offset paper prints, put the composite pieces into them, set for 24 hours, observe whether the composite parts "wrinkle." Such as "wrinkle" can determine the solvent resistance of the ink layer of the ink layer is weak, adaptability, there must be selective use, otherwise it shows that the pre-coating film adaptability is good, can be boldly used in the standard operation of a variety of printing composite.
The above-mentioned empirical test methods, though not scientific, are simple and intuitive and easy to grasp. As a means and method of management, it is convenient for self-inspection and mutual inspection of machine operators, and problems can be detected in a timely manner to avoid the appearance of defective quality products, which has a certain positive effect.
Sixth, the need for standardized operation At present, domestic pre-coated film still has many shortcomings, but compared with the "wet" compound, the composite quality is relatively stable. As the reform of old composite technologies and processes, the quality of stable composite products is also a direction. However, there are still many things to be done to stabilize the composite quality of domestic pre-coated films. Pre-coated film manufacturers should study how to improve their own quality, and users should continue to discuss the composite process. For correct and reasonable processes, we must emphasize the importance of standardized operations. Using standard operating techniques to make up for certain congenital deficiencies, give full play to the latent adaptability of the pre-coated film, so as to achieve better results, but also conducive to the accurate analysis, determination of quality accidents and take effective measures.
VII. Views and Requirements on Domestic Pre-coated Films 1. The pre-coating film is pollution-free, eliminating “wet†compound environmental pollution, harm to the human body and fire hazards, is a major step forward.
2. The use of pre-coating film simplifies the process operation, reduces the labor intensity of workers, eliminates many unfavorable factors of "wet method" combined with objective and man-made, and provides favorable conditions for improving the quality level of composites. It is a new process for paper-plastic composites. The application of technology clearly defines the direction.
3. The domestic pre-coating film production has just started, is still unstable, poor adaptability, and has certain limitations. In particular, weak solvent resistance, and low wettability and penetration of low-interfacial layers formed by multi-color overprinting are the key to the difficulty of the promotion of domestic pre-coated films. Pre-coated film producers should make necessary screening for material selection and structure of the adhesive layer.
4 uneven coating, poor rewinding, coating thicker, coating thickness, thin inconsistent, rewind loose, tight edges, wrinkles is also a major drawback.
5. It is imperative to improve the quality of the pre-coated adhesive layer and improve the adaptability to various types of prints as soon as possible. Reducing the specific gravity of the precoating film is also one of the directions for improving the quality of the precoating film.
The use of pre-coated membranes has changed the state of stagnation in China's lamination process and technology for more than ten years, and has taken a new approach to improving the quality of lamination in China. However, at present, there are many problems in the production of pre-coating films in the country, and the printing industry is still not
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