Second, the drug blister packaging aluminum foil printing coating process should pay attention to the problem
Pharmaceutical tablet and capsule packaging adopt blister packaging with industrial pure aluminum foil as base material. On pharmaceutical: PTP aluminum foil coating machine, gravure printing technology and roller coating method are used to print text patterns on the surface of aluminum foil and apply protection. Layer, the bonding process of coating the adhesive layer on the other side of the aluminum foil. The brief process flow is: aluminum foil unwinding → gravure printing → drying → coating protective layer → drying → coating adhesive layer → drying → aluminum foil winding. During the entire production process, the surface quality of the gravure printing text pattern and the heat sealing strength to be achieved by the adhesive layer, the adhesiveness of the protective layer and the drying temperature, and the speed and tension control of the coating machine operation are process operations. It needs to be strictly controlled. Therefore, in the "Aluminum Foil for Pharmaceutical Packaging" national standard, there is a clear requirement for the surface quality of the printed aluminum foil for medicinal use, and there are physical and chemical indicators for the performance of the protective layer and the adhesive layer, so that the protective pharmaceutical PTP aluminum foil has better Barrier properties, hygiene safety, heat sealability and good physical and mechanical properties. To achieve the above-mentioned requirements in the production process of PTP aluminum foil printing and coating, it is still necessary to be familiar with the applied raw material properties, and the following issues should be noted in the operation process.
1. Grasp the characteristics of aluminum foil and printing ink
The raw material used to produce PTP aluminum foil is industrial pure aluminum foil. Generally, the thickness is 0.02mm. If the aluminum foil thickness exceeds the required deviation (10%), the coating amount of the adhesive layer and the protective layer will be affected. Operator's attention. The tensile strength is 98 MPa, and the rupture strength is 90 kPa. The surface is clean, smooth, no wrinkles, no indentation damage, and no fluorescence. Because pinholes in aluminum foils are penetrating defects, drugs that are exposed to oxygen, water vapor, and light can degrade or deteriorate the efficacy of the drug. Therefore, the requirements for the pinhole degree are very strict. Generally, the pinhole degree of medical aluminum foil is required. The pinholes with a diameter of 0.1 mm to 0.3 mm per square meter should be less than one. The printing inks used in aluminum foils are mainly divided into two categories: one is poly- phenolamine inks. This type of ink has good adhesion, dispersibility, gloss, and abrasion resistance for printing on various types of substances. It has good solvent release properties and is soft and is used for printing plastic films. When used in the printing of aluminum foil materials, the excellent performance of the ink can be expressed, and its heat resistance can also meet the requirements of aluminum foil printing. The other type is a special aluminum foil ink mainly composed of vinyl chloride/vinyl acetate copolymer/synthetic resin/acrylic resin. It is characterized by its bright color, high concentration, particularly strong adhesion to aluminum foil, and good transparency. However, since it is used for gravure printing, its solvent volatility is large, and when it is used for medicinal PTP aluminum foil printing, it can easily cause the ink in the gravure roll ink hole to dry, deposit, and produce a paste plate phenomenon. Therefore, it is necessary to perform the deposition and freezing of the ink. Pretreatment. The method is to stir or freeze the deposited frozen ink (water bath). If the ink storage time is too long, the ink will appear to deposit, resulting in more ink on the top of the resin solution, the bottom of the paint more, the upper color light, the lower color, should be used after mixing.
2. The amount of solvent added to the ink should be appropriate
When a large-viscosity ink needs to be diluted with a large amount of diluent, it should be stirred while adding a diluent so that the diluent is evenly distributed throughout the ink. About 20s to 30s with a viscometer. Indoor temperature and humidity have an influence on the ink concentration. It is best to use an ink concentration detector to determine the amount of solvent added, and determine the ink concentration at regular intervals according to changes in temperature and humidity. When gravure printing is used to print aluminum foil products, the ink concentration is too low, which will cause the printed text pattern color to be not bright and the web pattern to be stenciled; if the ink concentration is too high, the pattern will have a crack phenomenon, which not only wastes ink, but also facilitates printing. The printed surface is uneven and not beautiful. In addition, the optimum ink concentration is selected according to the speed of the aluminum foil coater and the depth of the ink in the gravure roll.
3. The adhesive should meet the requirements
The adhesive of PTP aluminum foil is coated on the inner side of aluminum foil. Its role is to enable the aluminum foil and the medicinal PVC hard sheet to be firmly pressed together, so that the medicine in the plastic hard film blister is isolated from the outside, so that the medicine is sealed the goal of. In the process of heat-sealing the loaded drug, the adhesive layer is activated by the heat and pressure, so that it is firmly bonded with the PVC plastic hard film, which requires that the adhesive layer and the PVC resin should have good heat-sensitive properties and The compatibility of the substrate.
4. Drying temperature and time should be mastered during printing and coating process
The printed graphic and the adhesive layer and the protective layer need to be dried during the coating process. The drying of the aluminum foil surface coating needs a process, so it needs to stay in the drying tunnel of the device for a certain period of time. This depends on the speed of dry coating machine winding and the temperature level selected in the drying tunnel. The two should maintain a corresponding relationship. Due to the different thickness of aluminum foil material, physical and mechanical properties are all different, and the thermal expansion, contraction, and elongation of the material when running in the equipment are also somewhat different, so it should not stay too long at very high temperatures, otherwise aluminum foil It is also prone to wrinkling and surface discoloration. Generally, the drying temperature is controlled at 170°C-210°C.
5. Analysis of coating speed, coating tension, coating thickness and bonding quality
The coating thickness of the adhesive layer in the printing and coating process has a great influence on the bonding strength of the plastic PVC hard sheet. The adhesive layer is too thin. When the PVC hard film is hot pressed, the adhesive fastness may be reduced due to lack of material. Adhesive layer coating is too thick, not only increase the cost, but also need to extend the drying time, so it needs to be controlled within a proper thickness range. The coating thickness of the adhesive layer is affected by the binder concentration, coating tension, coating speed, and the number of anilox roller lines. In the case of coating roll pattern shape, depth, number of threads per inch and contact line pressure setting between the two rolls, the higher the adhesive concentration, the smaller the coating tension, and the faster the coating speed, the coating The thicker, so the thickness of the adhesive layer is generally adjusted by the concentration of the adhesive and the tension of the coater. Different types of aluminum foil have different requirements for the thickness of the adhesive layer. Generally, the thickness of the coating should be controlled between 3.5 μm and 7.0 μm. In the printing and coating of aluminum foil, the speed, temperature, and length of the three forces are related to each other, but also contain each other. The quality of the aluminum foil is directly related to the quality of printing and coating. If the speed of the printing press, the temperature in the drying tunnel, and the tension of the equipment are not controlled when the aluminum foil is printed and coated, it will cause product quality problems. For example, if the speed and tension control are not stable and the changes are different, the thickness of the printing and coating adhesive layer will be uneven and the depth of the printing artwork will be different. If the speed is too fast and the drying temperature is too low, it will cause printing and sticking. In the combined layer and the protective layer, the phenomenon of undulation does not occur; if the speed is too slow and the drying temperature is too high, the thermal deformation of the material will be too large, causing discoloration, folds, etc.; the tension is too large and the speed is slow. In the rewinding, it will cause left and right deviation, resulting in wrinkles, tears and other failures.
6. Strengthen the security of packaging printing
At present, the blister packaging PTP aluminum foil surface printing is very simple, monochrome printing is more common, almost no security signs and special anti-counterfeiting materials and methods, which provides counterfeiters with opportunities. In this regard, the advanced experience of foreign developed countries can be used for reference. According to reports, in the developed countries, there are nearly 10 kinds of anti-counterfeiting marks on a slap-sized pillbox, not only using micro-letters, glazing, and gravure printing techniques on banknotes, but also anti-counterfeit signs that can be visually recognized. Use a special lens to see the security signs. In addition, most of the pharmaceutical blister packaging surface also uses laser holographic dark anti-counterfeiting PTP aluminum foil products, the advantage of which is that the laser holographic pattern has strong intuitiveness and is easy for consumers to identify without affecting the original printing design and product packaging. The appearance does not affect the performance of using PTP aluminum foil material. This anti-counterfeit product is a counterfeiting method adopted by many multinational pharmaceutical companies. The application of invisible fluorescent anti-counterfeit PTP aluminum foil is also one of the development trends of pharmaceutical packaging technology in the future. This anti-counterfeiting effect is more subtle and difficult to observe with the naked eye, but the anti-counterfeiting mark or pattern text under the UV lamp will be clearly exposed. At present, some blister packaging manufacturers in China have already been applied, but the total amount used is still very small. On the whole, China's pharmaceutical packaging companies are still relatively backward in terms of anti-counterfeiting technology. Although we have seen alarming cases of counterfeit drugs in the pharmaceutical market, awareness of the importance of anti-counterfeiting technology and use has gradually increased, but in the new security materials and anti-counterfeiting technology The research and development application is still not satisfactory and must be taken seriously. In the future, it is necessary to increase the use of high-tech anti-counterfeiting technology. One or more hi-tech anti-counterfeit technologies can be used for pharmaceutical packaging, such as digital anti-counterfeiting, ink security, special printing anti-counterfeiting, nuclear track anti-counterfeiting, biological anti-counterfeiting, and DNA anti-counterfeiting. Technology is the development direction of drug packaging anti-counterfeiting applications in the future.