Packaging printers teach you partial matte printing techniques
With the increase of shopping malls and goods, many enterprises and box manufacturers like to reach the role of partial matte on the outer packaging to improve the product grade and anti-counterfeiting function. Generally speaking, partial matte is achieved by counter-printing matte oil. It can be said that the counter-printing matte oil skills through the counter-printing matte ink to reach a similar function of washing aluminum. But there is another function in matte oil is to replace the original matte film, more sensitive to meet the personalized needs of customers; this is also the reason why many of the packaging selection part of the matte printing skills.
A, production considerations
1, raw materials
Plastic film needs to be printed on the printing side of the corona, the corona value should reach at least 38 daine or more to allow the oil to have sufficient adhesion to adhere to the film. Therefore, it is necessary to select the film for matte oil reverse printing to have a sufficient corona value. So in the film material selection, generally PET, BOPA, these two raw materials are better.
Under normal circumstances, BOPP raw materials are not suitable for reactive matte oil, on the contrary, PET, BOPA non-corona surface corona value can reach more than 38 daine, so can meet the requirements. However, in the process of use, it is still recommended double corona, in order to be more secure, to ensure that the adhesion of matte oil printing to reach the quality requirements of scratch and wear resistance.
Printing plate planning, matte oil copper plate graphic planning is reversed, so the surface printing on the film substrate, and therefore its layout planning is reversed, that is, the same as the printing plate is the reverse sort. Under normal circumstances, the surface printing matte oil are field printing practice, therefore, the copper plate printing plate carving depth will have certain requirements. According to the parameters provided by the supplier of matte oil applied by each company, the depth of engraving of the printing plate is decided. As a rule, this kind of reverse printing matte oil will not do the hanging network, shallow network, transition network and other processes, because these processes themselves will weaken part of the main highlight of the bright light.
Matte oil itself needs to reach the role of matte. First, the degree of matte according to different needs will have different requirements. And on the other hand, because so the table printed on the film substrate, so the reverse printed matte oil directly exposed in the packaging exterior, in the packaging, delivery and sales process, will be in direct contact with the outside world, and therefore its scratch resistance must be more than the general lining printed oil, the need to evaluate the risk of its risk of being scratched off, whether it meets the food or non-food high health risk performance requirements.
This aspect is a test of the matte oil production supplier’s own skill strength, as well as flexible packaging production enterprise equipment process.
General matte oil will not be used on the outer packaging alone, but will be printed on the inner layer at the same time in cooperation with the use of the surface layer, in order to highlight the unique role of reverse printing matte oil.
Therefore, gravure printing machine needs to have reverse printing rotary equipment, in order to cooperate with the overprinting requirements. Previously, some enterprises have also tried to print twice to reach the role of surface printing, but it has been proven that, both from the quality requirements and the role of registration, it is difficult to achieve the original intention.
Second, the printing process is simple to present the problem
1, counter-printing matte oil is scratched
Such anomalies are mainly concentrated in the equipment, especially on the rotary frame, as well as the guide roller above, are very simple to present. This is not clean on the rotary frame guide roller, foreign objects, etc. formed.
2、Printing material simple wrinkle
Conventional because its material needs to go through the rotary frame, is a process from the inside to the surface printing, the smoothness of the rotary frame and the smoothness of the material is very important, a careless, inattentive, it is easy to form the printing semi-finished substrate crease.
3, reverse printing matte oil blocking plate
Because the dummy oil requirements to achieve scratch resistance, its viscosity is relatively high, on the other hand, the dummy oil particles than the general printing oil particles will be much larger, and therefore very simple to present blocking plate, present on the dummy oil phenomenon, therefore, in the printing transfer process, when the machine is turned on, should pay great attention to the printing plate is clean and clean, to ensure that there is no blocked situation.
4, solvent residue aspects
General matte oil layout are field, and the area of the general relative proportion will be larger, the amount of ink on the larger; on the other hand, because the printing and table printing together, according to the order, matte oil for the final color sequence, and therefore through the oven moment is very little, and after the winding up the printing and table printing will become a film and film between the oil in a laminated surface, simple to let the solvent penetrate each other, hidden in the matte oil or printing ink layer, it is difficult to evaporate out, so it will become more difficult to eliminate the remaining solvent residue. Therefore, it will become more difficult to eliminate the remaining solvent, thus leading to solvent residual overspending phenomenon. According to this feature, in the compounding process should be reduced machine speed, progress in the role of exhaust air, in order to reduce the total amount of solvent residues.
5、Dummy oil anti-sticky
Similar to the inductive elements of point 4, dummy oil drying capacity is not enough, simple occurrence of dummy oil itself anti-viscosity, at the same time, will occur dummy oil and printing oil in the mutual anti-viscosity situation. Therefore, the drying capacity of the oven in the printing equipment is very important.
6, matte oil matte effect is poor
In the printing process, if the matte oil viscosity control is not good, matte oil matte effect will be poor; at the same time, the matte oil itself matte effect is not ideal, will also present such problems;;
7, matte oil scratch resistance
Now, matte oil is divided into general matte oil, high concentration of matte oil, high temperature matte oil, companies should select different grades according to their needs. Now there are some domestic suppliers do a good job, the resolution of the role of matte oil scratch resistance is the adhesion of matte oil.
Third, composite notes
1, dummy oil in the compounding process to show anti-viscosity appear
Mainly from the dummy oil wear resistance and dummy oil drying degree and composite oven temperature and hot press roller temperature and other aspects of the search for reasons.
2, after compounding solvent residue overspending
This problem point is similar to the printing problem point 4, but there are differences. In the compounding process, such problems will be more prominent, therefore, to very carefully control the machine oven temperature, compounding speed and oven exhaust, etc.
3、Compound peel strength
Anti-printing dummy oil of the substrate on the composite related to the structure of other non-anti-printing dummy oil, its peel strength is on the low side, this aspect of the experience analysis, mainly dummy oil contains a kind of smooth precipitates, especially the substrate for PET raw materials structure, more obvious. This aspect needs to go through the function of the glue and the amount of glue to change, of course, the basic still has to improve from the matte oil itself, in order to cure the root.
Four, bag-making common problems
1, sealing edge dummy oil whitening
This is mainly due to two major reasons: one is whether the dummy oil resistance to meet the requirements, the second is the bag-making machine on the heat sealing knife whether the temperature is too high, the pressure is too large formed.
Reverse printing matte oil applied to the zipper bag, the zipper head at the simple separation, this aspect with the composite strength and will have a certain relationship, and the composite strength itself, and with the reverse printing matte oil.
Our packaging box printing factory once with the same structure of raw materials for a set of experiments, in addition to dummy oil process changes, other glue, printing, bag-making machine temperature, pressure, etc. are common when comparing, found that no dummy oil printed bags, did not present the zipper location off-layer phenomenon, and counter-printed dummy oil, will present the phenomenon of separation. Based on this experiment, the matte oil on the composite strength and the temperature resistance of the bag-making is a certain impact.
Therefore, on such anti-printing matte oil zipper bag products, pre-production to fully assess its production process process control issues to avoid unnecessary abnormalities.
3、Matte oil is scratched
Reverse printing matte oil is directly printed on the film substrate, if the machine components are not cleaned effectively in a timely manner, matte oil will be very simple to be scratched, and therefore in the finished process to catch the machine cleaning operations thoroughly.