The application of the hottest masking tape in fle

  • Detail

Application of plate pasting tape in flexographic printing

in the process of flexographic printing, the application of plate pasting tape has always been a matter of concern. Mr. Wu Lianzhen from Desha tape Shanghai Co., Ltd. introduced the selection and use of plate pasting tape to us

with the development of China's national economy, especially the development of food, household chemicals, washing products, medicine, cosmetics, household appliances and small household appliances, logistics and other industries, the label industry has correspondingly experienced a high-speed growth, with an annual growth rate of 15% - 20%, becoming the fastest-growing sub industry in the printing industry

flexographic printing is a technology that uses flexible plates and transfers ink through the roller to realize printing. Compared with traditional printing technologies such as offset printing, gravure printing and relief printing, flexographic printing has the advantages of less equipment investment, short plate making cycle, fast printing speed, strong adaptability to substrate, and the use of environmental friendly ink. At present, in the field of packaging and printing in Europe and America, the popularity of flexographic printing is very high, and it can even reach 90% in the United States. In recent years, with the progress of technology and the enhancement of environmental awareness, flexographic printing has been increasing in the proportion of China's printing industry, and has gradually become a widely favored printing technology. From the perspective of the development trend of printing technology in the global label market, flexographic printing is also one of the fastest-growing label printing technologies in the past

different from other printing technologies, flexographic printing requires the plate to be pasted on the plate roller or sleeve, so the plate pasting tape is required. The function of the plate pasting tape is mainly to fix the position of the printing plate, ensure that the printing plate will not fall off or shift during the printing process, and buffer part of the pressure on the plate to improve the printing effect. It is a very important link in the printing process to stick the plate on the plate roller or drum, so it is very important to choose the appropriate plate sticking tape. The plate pasting tape in flexographic printing is mainly double-sided pressure-sensitive tape, which can be divided into foam tape and non foam tape according to the different substrates. The base material of non foam tape includes film or cloth base, which is rarely used in label printing. Therefore, this paper mainly introduces the basic safety matters of foam 4 and fatigue testing machine in the use process, and discusses the problems often encountered by customers in the use process

introduction to plate pasting foam tape

a good foam tape can not only fix the plate, but also improve the printing quality. Taking the Desa softprint series as an example, the typical foam tape composition includes glue, foam, stabilizing film and release paper. Glue is coated on both sides of the tape and pasted on the plate and the plate roller respectively to fix the plate. Foam is an important part of plate adhesive tape. Through the density of foam substrate, the printing pressure can be finely controlled to improve the printing effect. There are three aspects that affect the characteristics of foam: the cell structure of foam, the compression recovery rate of foam and the hardness of foam. Compared with irregular bubbles, round and evenly distributed bubbles can provide high-quality and stable field and dot printing effects

good foam compression recovery rate can ensure stable printing quality and prolong the service life of the tape. The density of foam determines the soft hardness of foam. Different soft hardness of foam can produce different points and field printing effects, which is an important factor in the selection of tape. The stable film in the tape can prevent the stretching of foam during plate pasting and plate pasting relocation, and provide a uniform stress area during the printing process. The function of release paper is to prevent adhesive tapes from sticking to each other. Release paper with concave convex surface can also help eliminate bubbles in the process of plate pasting

selection of stencil foam tape

how to choose a suitable stencil tape can be considered from the following aspects:

1 In terms of foam tape, thickness generally refers to the thickness when printing under pressure, and the thickness when not under pressure is generally slightly thicker. The thickness of the plate pasting tape will affect the printing repetition circumference selected according to the manufacturing process, and will also affect the printing quality to a certain extent. Generally speaking, the thicker the tape, the larger the space for adjusting the printing effect. However, flexographic printing machines have their own inherent requirements for the thickness of tape. For label flexographic printing, 0.38mm thick plate adhesive tape is mainly used. It should be pointed out that when calculating the printing gap of flexographic printing, the thickness of the plate pasting tape should be taken into account

2. The primary function of the plate pasting tape is to display the experimental data and results. The developed experimental machine products firmly fix the printing plate on the plate roller or sleeve, and the manufacturers of the plate pasting tape usually take the peel strength of the tape on the surface of the plate or sleeve as the general index of the tape viscosity. The higher the peel strength of the tape, the stronger the viscosity and the firmer the adhesion. However, in the process of plate pasting, repositioning, printing and plate unloading, the adhesion between the tape and the plate surface is different. The ideal glue is to keep the same viscosity throughout the process, but in practical application, due to the use of pressure-sensitive glue, the viscosity of some manufacturers' tape products gradually increases in the late stage of printing, resulting in difficulties in plate unloading, while good tape products will have a viscosity that changes little in printing. The glue viscosity of one side of the plate sticking tape and the one side of the plate roller is often designed differently. Generally, the high viscosity is for reliable plate sticking and avoiding plate warping, and the low viscosity is for convenient plate relocation and plate unloading, or it is easy to unload the tape without leaving residual glue. The specific choice depends on the operating habits and requirements of the printing enterprise

3. The printing pattern is usually divided into point and field, and different printing effects are achieved mainly by selecting different soft and hard plate pasting tapes. In terms of foam tape, super soft tape can achieve the finest dot printing, or make up for the impact of gear runout on Printing (ink bar); Soft adhesive tape meets fine dot printing; Neutral adhesive tape meets comprehensive printing; The hard adhesive tape meets the good field effect

4. At present, the development trend of label printing is that there are many varieties, small printing volume and short cycle, so the quality stability and ease of operation of tape have become more and more important. When selecting tape, better product quality and good operating performance also need to be considered

problems that should be paid attention to in application

the effect of plate pasting depends on each process in the plate pasting process. The correct use of plate pasting tape can improve the printing quality

1. Temperature has a great influence on the use of plate adhesive tape. All operations should be carried out at room temperature to avoid affecting the viscosity due to temperature

2. Before pasting the plate, the surface of the plate and the plate roller should be kept clean. Dirt such as dust, rust and ink will damage the adhesive force of the tape, resulting in poor adhesion and warping. High concentration alcohol should be used for the cleaning of plate and plate roller, because other chemical solvents may damage the plate or sleeve

3. When pasting a plate, the area of the tape should be larger than the area of the plate, so the edge of the tape should be larger than the edge of the plate, which can greatly reduce the risk of warping

4. When pasting the plate, the interface of the plate and the interface of the tape should be avoided. If the interface of the plate is facing the interface of the tape, it is easy to cause the printing plate at the interface to stick loosely, curl edges, and the printing plate to fall off

5. Do not roll the tape directly by hand when pasting the tape. Take the double-sided tape and remove part of the release paper on one side. Don't open all the release paper immediately. After a part of the tape is fixed, remove the release paper gradually. Stick the tape onto the plate cylinder according to the position of the plate. In the process of pasting, because the pressure of hand on the tape is uneven, if you roll the tape by hand, it is easy to form small bubbles, which may also damage the fine points. A soft rubber roller can be used to evenly distribute and compact the tape. The rolling method is that this kind of material is compacted in a herringbone track from the middle to both sides under the action of light, so that the air in the middle of the tape can be squeezed out. At present, there is a kind of roller with needle on the market, which is also very effective for eliminating bubbles

6. After the printing plate is pasted, in order to prevent the ink and solvent from contacting the adhesive tape and the adhesive at the edge of the plate during printing and cleaning, a ring of edge banding tape can be pasted around the plate to avoid warping. The thickness of edge banding tape should be thin

7. When unloading the plate, it is recommended to unload the plate slowly and smoothly at an angle of less than 90 (the tangent angle between the unloaded plate and the surface of the drum), so as to avoid wrinkles or cracks of the plate. The slower the plate is unloaded, the weaker the adhesion to the tape plate. On the contrary, the faster the plate is unloaded, the stronger the adhesion. When unloading the tape, the method is the same as that of unloading the plate

flexo is a fine printing process, and many variables need to be controlled. As manufacturers have higher and higher requirements for label printing quality, the process control of each printing process is becoming more and more important. I hope that the simple discussion of plate pasting tape in this paper can help you

Copyright © 2011 JIN SHI