1. 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 0.02mm, the tensile strength is 98kPa, the bursting strength is 90kPa, the surface is clean, flat, no wrinkles, no indentation damage, no flakes, no surface. The wetting tension is not less than 32. The requirement for the pinhole of the medicinal aluminum foil is that the pinhole having a diameter of 0.1 - 0.3 mm is not more than 1 / m2. Since the pinhole in the aluminum foil is a penetrating defect, the drug is degraded or deteriorated by the intrusion of oxygen, water vapor and light, so the requirement for the pinhole is very strict; in addition, if the thickness of the aluminum foil exceeds the required deviation ( When it is 10%), it will affect the coating amount of the adhesive layer and the protective layer, and it is necessary to attract the attention of the operator.
Printing inks for aluminum foil are currently mainly divided into two categories: one is a polyamide ink. This kind of ink has good adhesion, dispersibility, gloss, abrasion resistance, solvent release, softness and is used for the printing of plastic film. When used for printing aluminum foil materials, the excellent properties of the inks can be expressed, and the heat resistance can also meet the requirements of aluminum foil printing. The other type is an aluminum foil special ink containing vinyl chloride vinyl acetate copolymer synthetic resin/acrylic acid resin as the main component, and its holding point is bright color, high concentration, strong adhesion to aluminum foil, and good transparency, but Since it is used for gravure printing, its solvent volatility is large, and it is easy to cause the ink in the intaglio roll in the gravure roll to dry and deposit when used for medicinal PTP aluminum foil printing, resulting in a paste phenomenon. Therefore, it is necessary to perform necessary pretreatment of the deposition and freezing of the ink by stirring or increasing the temperature (water bath) of the deposited frozen ink. If the storage time of the ink is too long, the ink will deposit, resulting in more resin in the upper layer of the ink, more pigment in the lower layer, lighter color in the upper layer, and darker color in the lower layer. It should also be stirred and used.
2, the amount of solvent added to the ink should be appropriate
When a high viscosity ink needs to be diluted with a large amount of diluent, it should be stirred while adding a diluent to evenly distribute the diluent throughout the ink. The meter is measured between 20-30s. The indoor temperature and humidity have an effect on the ink concentration. * The ink concentration detector is used to determine the amount of solvent added, and the ink concentration is measured at regular intervals according to changes in temperature and humidity. When the aluminum foil product is printed by gravure printing, the ink concentration is too low, which will cause the printed text pattern to be not bright and the paste is generated at the texture; if the ink concentration is too high, cracks will occur at the image, which not only wastes ink, but also It is easy to cause the printing surface to be uneven and not beautiful. In addition to this, the ink of * is selected according to the speed of the aluminum foil printing coater and the depth of the ink mark of the printing gravure roll.
3, the adhesive should meet the requirements
The adhesive of PTP aluminum foil is coated on the inner side of the aluminum foil, and its function is to make the aluminum foil and the medicinal PVC hard sheet firmly heat-pressed, so that the medicine in the plastic hard sheet blister is separated from the outside to achieve the sealing of the medicine. purpose. During the heat sealing process of loading the drug, the adhesive layer is activated by the hot pressing action, thereby firmly bonding with the PVC plastic hard piece, which requires the adhesive layer and the PVC resin to have good heat sensitivity and the substrate. Compatibility.