Analysis of PTP Packaging Printing

After filling the product in a vacuum bubble (bubble) or a molded blister, a cover material is used, and the pressure is sealed at a certain temperature and time with the bubble-forming substrate. This type of packaging is called a bubble. Cover packaging.
The blister pack of pharmaceuticals is one of the main forms of pharmaceutical packaging and is suitable for the mechanized packaging of solid pharmaceuticals such as tablets, capsules, suppositories, and pills.
Pharmaceutical packaging aluminum foil commonly known as PTP aluminum foil, PTP is an acronym for Press Through Packaging, literally translated as "packaged by pressure," the industry's more formal title for pharmaceutical packaging aluminum foil, also known as blister packaging aluminum foil. PTP aluminum foil is a relatively customary expression in Asia, not a complete expression. In Europe, the English expression of PTP aluminum foil is Push-through Foil. In Chinese, it is “openable aluminum foil”. China's title for PTP aluminum foil used in pharmaceutical packaging materials and container registration certificates is: PTP aluminum foil for pharmaceutical packaging.
Pharmaceutical blister packaging materials are basically aluminum foil, due to the use of PTP packaging, the contents are clearly visible, the surface of the aluminum foil can be printed with a unique design, easy to identify patterns and logo description text. At the same time, aluminum foil has good barrier properties, light weight and certain strength. When it is pressed, it can be broken by a little pressure. Therefore, it is convenient for taking medicine and because it is convenient to carry, it is widely used in the pharmaceutical field. .
As early as the 1930s, pharmaceutical blister packaging began to be used in Europe and steadily advanced. In China, pharmaceutical blister machines were introduced in the early 1970s, but blister-packed PTP foils were imported. It was not until around 1986 that the country began to introduce more advanced PTP production lines for large-scale production. At that time, domestic PTP aluminum foil production materials needed to be imported. The annual output of PTP aluminum foil was about 420 tons, and most of them were plain foil or single-sided printed foil varieties, which basically could meet the needs of the domestic pharmaceutical industry for blister packaging because domestic pharmaceuticals at that time were Most of them still use old-style glass bottles and other packaging forms.
In the late 1980s and early 1990s, with the continuous deepening of China’s reform and opening up, international exchanges continued to increase. Foreign pharmaceuticals that use advanced technology packaging began to flood the country, and the domestic pharmaceutical market was impacted. In order to improve the competitiveness of pharmaceuticals, the decision-makers in the pharmaceutical industry must first replace the pharmaceutical packaging and adopt PTP packaging with superior performance in all aspects to achieve the modernization and gentrification of pharmaceutical packaging and decorating, which quickly stimulates The development of PTP packaging production and continuous development of new products.

The finished product of the aluminum foil mainly includes three parts: OP layer (protective layer), VC layer (adhesive layer) and aluminum foil substrate, as shown in FIG. 1 . Among them, two printing layers are mainly printed on one side or on both sides according to customer's requirements, but sometimes they are not printed. In the following explanation, the printing of PTP aluminum foil will be described as a printed layer finished product. PTP aluminum foil production process and quality control shown in Figure 2.

Plate cylinder production

Aluminum foil printing mainly uses gravure printing, which is divided into two stages, namely: production and printing of printing cylinders.
The production of plate cylinders is the key to the whole process and will directly restrict the effect of aluminum foil printing. The factors that play a decisive role in the production of plate cylinders are the number of engraving lines, the size of the letters, and the engraving method.
The design of the plate cylinder is divided into stars according to layout. 50% dislocation, full layout. There are various ways such as being in a row, but the layout of each layout depends mainly on the buyer, mainly based on its requirements and its existing equipment. In these arrangements, the full-star method is a relatively simple one, as long as the design of the design of the size of the model, to ensure that no matter what the location in the cut, there is a complete unit on the medicine board. The most difficult is the text unit has a fixed seamless typographic layout (full version), which requires the text unit offset angle is fixed, and according to the effective version length to calculate the unit coordinates, the difference is insignificant, with thousands of miles. There are several other ways to make the difficulty between the above two. From the current market demand situation, seamless typography will gradually become the mainstream of the market with its beautiful design.
After the design of the text layout is completed, or for experienced designers to get the design drafts from them, it is already understood which type of engraving method is used for the plate cylinder. The production of plate cylinder mainly includes corrosion, electric carving and laser production. Corrosion version of the text unit requirements is that the text should have a relatively coarse strokes, the spacing is slightly larger; and the laser version can make the text to achieve a very small effect, and even laser holographic anti-counterfeiting technology can guarantee the application; With its economic advantages, it has occupied the dominant position of the market. As the requirements of manufacturers continue to increase, new creative packaging continues to be available, and the laser version will have a large market.
In addition to the fine pattern design and excellent engraving, a good plate cylinder also considers the diameter of the plate cylinder. For printing equipment, the diameter of the plate cylinder is a key. Plate cylinders restrict multi-color overprinting and even determine the print quality. For the engraving of text, the number of lines is mainly considered. In the past, plate cylinder suppliers generally used a single number of engravings, but as more and more new creative packagings were launched, people put forward new requirements for aluminum foil printing, that is, the gradual change of colors in aluminum foil printing even The colors show a variety of effects, requiring the plate cylinder to have multiple lines or even continuous changes in certain areas.

Aluminum foil printing

Of course, aluminum foil packaging production companies, the most important stage is aluminum foil printing.
For gravure printing, the international standards GBl2255-90, YBB00152002 "Aluminum Foil for Pharmaceutical Packaging" (Trial) have clear requirements for the quality of aluminum foil printing. In printing, the main considerations are the viscosity of the ink, the degree of finish, and the avoidance of misplaced printing. The ink used in aluminum foil printing is oily, rather than printing ordinary paper ink; and aluminum foil is metal, it will not fully absorb the moisture on the printing ink like paper, but will evaporate water through the printing equipment drying system. . As the ink goes through the drying system, the temperature of about 200°C is required in the coating process and the pharmaceutical production process. In view of this, it is required that the color of the printing ink cannot be changed at a high temperature and the viscosity thereof cannot be reduced.
To achieve the above requirements in the production process, the following points must be controlled during the operation of the PTP foil printer:
(1) Grasp the viscosity of the ink. The optimum ink viscosity is adjusted according to the speed of the printing press and the depth of the ink hole in the gravure cylinder. Ink viscosity is too low, will result in printed text and pattern color is not bright, paste lines appear at the network line; ink viscosity is too high, it will cause the squeegee at the circumferential direction points do not enter the ink, the pattern will appear crack phenomenon, not only The ink is wasted, and it is easy to cause the print surface to be uneven and look unattractive.
(2) The correct use of thinner. The ink with high viscosity needs to be diluted with a large amount of diluents. Generally, the viscometer is used to measure and adjust the viscosity to a suitable point. In order to make the needle-shaped ink dots on the spot, the writing lines have no broken pens, and the word line has no broken pens.
In recent years, with the development of the pharmaceutical packaging industry, people are increasingly demanding the color of pharmaceutical packaging. Two-color. Tri-color, even multi-color printing has gradually become the mainstream of the market. The color printing of aluminum foil requires a very accurate color registration, and now the new device uses a computer to automate the cursor. In multi-color printing, it is firstly necessary to ensure that gravure cylinder registration is very accurate, and secondly, skilled workers are required to guarantee the completion of this process. Our company is at the forefront of this field in this field. With the purchase of several sets of domestic advanced equipment and more than 10 years of operational experience, we can provide customers with products that fully meet their needs. In multicolor printing, the use of ink to form a new color of the superposition of the ink and printing requirements are higher, the ink used in addition to a certain viscosity, it must also have a certain affinity with other colors of ink, otherwise Because of the affinity or stickiness, the heat seal strength of aluminum foil is directly affected. In severe cases, even the aluminum foil loses heat sealing performance.

Coating of adhesives

Adhesive coating seems to be more important than aluminum foil printing. The national standard GBl 2255-90 and the national standard YBB00152002 (for trial implementation) require that the total coating amount of the protective layer and the adhesive layer should reach (5±1) g/m2. The function of the adhesive layer is to make the PTP aluminum foil and the PVC hard film able to be firmly hot-pressed to seal the medicine. In the sealing process, the adhesive layer is activated by the heat and pressure, so that it can be firmly bonded with the PVC hard sheet. This requires that the resin of the adhesive layer should have good heat-sensitive properties and compatibility with the substrate.
The adhesive layer needs to be dried after coating to volatilize the solvent therein. The residence time of the coated product in the drying tunnel depends on the speed of the coiler and the temperature in the oven. Due to the thermal expansion, cold shrinkage, and ductility of aluminum foil materials, there is a certain gap, so it is not appropriate to stay at high temperatures for too long, otherwise aluminum foil is also prone to wrinkling and surface discoloration. Therefore, the drying temperature and drying time should be strictly controlled.
The thickness of the adhesive layer should be controlled within a certain range. The thickness of the adhesive layer has a great influence on the adhesive fastness. The adhesive layer is too thin. When the PVC hard film is pressed hot, the adhesive fastness may be reduced due to lack of glue; if the adhesive layer is too thick, the adhesive fastness may also be reduced and the cost may be increased. At the same time, it is necessary to ensure uniform distribution of the amount of coating, and the national standard specifies that the error cannot exceed ±12.5%.
The coating amount of the adhesive layer is affected by the binder concentration, coating tension, and coating speed. The greater the binder concentration, the smaller the coating tension, and the faster the coating speed, the thicker the coating layer. The coating speed is determined by the residence time, so the thickness of the adhesive layer is generally controlled by adjusting the concentration of the binder and the tension of the coater. Different types of aluminum foil have slightly different requirements for the thickness of the adhesive layer, but generally 3-4g/m: is appropriate. In addition to coating the VC glue used for heat sealing, an OP adhesive for protecting printed characters is also applied on the printed layer of the aluminum foil. The unqualified aluminum foils on the market are mainly coated with the following points.
(1) Uncoated protective agent (OP adhesive)
This is the most common and most prominent issue. The protective layer is coated on the surface of the printed aluminum foil. Its role is:
1 to prevent the surface of the ink layer wear off, while improving the heat resistance when the bubble cover heat sealing;
2 Prevent PTP aluminum foil from being contaminated by the contact between the outer layer ink and the inner layer adhesive during winding;
3 Prevent the self-oxidation and deterioration of the surface of aluminum foil, do not apply the protective layer or the undercoating of the protective layer. When the bubble cover is heat-sealed, it often finds that the printed text pattern is blurred and peeled off.
(2) Polyurethane Adhesive (VC Adhesive) Adhesive layer Non-uniform adhesive coating is uniform and there is no glue leakage, which will directly affect the heat sealing quality of the blister packaging, that is, the sealing performance. The thickness of the adhesive layer has a great influence on the adhesive fastness. The national standard requires that the coating amount of the VC adhesive be (4±0.5) g/m2.
After the foil has been printed and coated, it must be cut into small rolls of various widths according to the customer's requirements. The most important aspect of the link is to ensure that the end face of the small roll of aluminum foil is neat.

Color foil production

In past production, printing foil was mainly used, but with the continuous emergence of new creative packaging, color foil has gradually become the darling of the market.
The production of colored pharmaceutical PTP aluminum foil is to evenly stir the pigments or dyes of various colors into the protective agent and adhesive, and then apply the protective agent and adhesive to the pharmaceutical PTP aluminum foil to make the medicinal PTP aluminum foil. Protective layer and sticky