Characteristics of Aluminum Foil and Printing Ink

       At present, blister packaging is becoming more and more popular in the packaging of health food and medicine tablets and capsules. Blister packaging, also known as PTP (press through packaging), is a combined process of using industrial pure aluminum foil as the base material, printing text patterns on the surface of aluminum foil by gravure printing technology and roll coating method, coating protective layer and coating adhesive layer on the other side of aluminum foil.Characteristics of Aluminum Foil and Printing Ink

        The brief process flow of PTP aluminum foil packaging is as follows: aluminum foil unwinding, gravure printing, drying, coating protective layer, drying, coating adhesive layer, drying and aluminum foil winding.Characteristics of Aluminum Foil and Printing Ink

       In the whole production process, the surface quality of gravure printed text patterns, the heat sealing strength to be achieved by the adhesive layer, the adhesion and drying temperature of the protective layer, as well as the speed and tension control of the coating machinery need to be strictly controlled in the process operation.

Master the characteristics of aluminum foil and printing ink

       The raw material used for the production of PTP aluminum foil is industrial pure aluminum foil. Generally, the thickness is required to be 0.02mm, the tensile strength is 98kpa, the rupture strength is 90kpa, the surface is clean, flat, free of wrinkles, indentation damage, no flake fluorescent substances, and the surface wetting tension is not less than 32. Characteristics of Aluminum Foil and Printing Ink

       The requirement for the pinhole of aluminum foil for medicinal and health food is that the pinhole with diameter of 0.1-0.3mm shall not be more than 1 / m2. Because the pinhole in aluminum foil is a penetrating defect, the efficacy of health food and drugs will be reduced or deteriorated by the invasion of oxygen, water vapor and light, so the requirements for pinhole are very strict; In addition, if the thickness of aluminum foil exceeds the required deviation (10%), it will affect the coating amount of adhesive layer and protective layer.Characteristics of Aluminum Foil and Printing Ink

       At present, the printing inks for aluminum foil are mainly divided into two categories: one is polyamide ink. This kind of ink has good adhesion, dispersion, gloss, wear resistance, good solvent release and softness for the printing of various substances. It is mostly used for the printing of plastic films. Characteristics of Aluminum Foil and Printing Ink

       When used in the printing of aluminum foil materials, the excellent properties of the ink can be shown, and its heat resistance can also meet the requirements of aluminum foil printing. The other is the special ink for aluminum foil with vinyl chloride vinyl acetate copolymer synthetic resin / acrylic resin as the main component. It is characterized by bright color, high concentration, strong adhesion to aluminum foil and good transparency.Characteristics of Aluminum Foil and Printing Ink

       However, due to its high solvent volatilization when used in gravure printing, it is used in health food During surface printing of pharmaceutical PTP aluminum foil, it is easy to cause ink drying and deposition in the ink hole of gravure roll, resulting in plate pasting. Therefore, it is necessary to carry out necessary pretreatment for the deposition and freezing of the ink.Characteristics of Aluminum Foil and Printing Ink

        The method is to stir the deposited and frozen ink or increase the temperature (water bath). If the storage time of the ink is too long, the ink will deposit, resulting in more resin solution in the upper layer, more pigments in the lower layer, light color in the upper layer and deep color in the lower layer. It should also be used after stirring evenly.Characteristics of Aluminum Foil and Printing Ink

The amount of solvent added to the ink should be appropriate

        When the ink with high hiding degree needs to be diluted with a large amount of diluent, it should be stirred while adding diluent to make the diluent evenly distributed in the whole ink. The measuring time of the instrument is about 20-30s.Characteristics of Aluminum Foil and Printing Ink

       Indoor temperature and humidity have an impact on the ink concentration. It is best to use the ink concentration detector to determine the amount of solvent added, and measure the ink concentration every certain time according to the changes of temperature and humidity. Characteristics of Aluminum Foil and Printing Ink

       When using intaglio printing to print aluminum foil products, the ink concentration is too low, which will cause the color of printed text and pattern is not bright, and the paste phenomenon will occur at the anilox;Characteristics of Aluminum Foil and Printing Ink

       If the ink concentration is too high, cracks will occur at the drawing, which not only wastes ink, but also easily causes uneven and unsightly printing surface. In addition, the best ink should be formulated according to the speed of aluminum foil printing coater and the inking hole depth of printing gravure roller.Characteristics of Aluminum Foil and Printing Ink

The adhesive shall meet the requirements

        The adhesive of PTP aluminum foil is coated on the inner side of the aluminum foil. Its function is to firmly press the aluminum foil and medicinal PVC hard sheet, so as to separate the drugs in the plastic hard sheet Blister from the outside, so as to achieve the purpose of sealing the drugs. Characteristics of Aluminum Foil and Printing Ink

      In the process of loading drugs for heat sealing, the adhesive layer is activated by hot pressing, so as to be firmly bonded with PVC plastic hard sheet, which requires that the adhesive layer and PVC resin should have good heat sensitivity and compatibility with the substrate.Characteristics of Aluminum Foil and Printing Ink

Master the drying temperature and time for printing and coating

      The printed picture and text, adhesive layer and protective layer need to be dried in the coating process. The drying of the surface coating of aluminum foil needs a process, so it needs to stay in the drying channel of the equipment for a certain time, which depends on the winding speed of the coating machine and the temperature selected in the drying channel. Characteristics of Aluminum Foil and Printing Ink

       The two should maintain a corresponding relationship. Due to the different thickness of aluminum foil materials, there are differences in physical and mechanical properties, and there are certain differences in the thermal expansion, shrinkage and elongation of materials during operation in the equipment, so they should not stay at very high temperature for too long, otherwise the aluminum foil is also prone to wrinkling and discoloration. Generally, the temperature of drying channel should be controlled at 170 ℃ – 210 ℃.Characteristics of Aluminum Foil and Printing Ink