Application Status and Development Trend of Aluminum Foil Printing Materials

The aluminum foil printing and blister packaging of Shandong Packaging Research Institute's pharmaceuticals began in Europe in the 1930s. The application of aluminum foil as printing material in China in the early 1970s mainly relied on imports. In the 1980s, Japan has introduced Japan's pharmaceutical aluminum foil printing and coating equipment from Guangzhou, Lianyungang, and Jinzhou, but major printing materials still need to be imported. In the 1990s, China could not only manufacture single-color medical aluminum foil printing and coating equipment, but also manufacture or print colored, gold-colored pharmaceutical packaging aluminum foil products. The inks and adhesives used in aluminum foil and aluminum foil for printing materials used in pharmaceutical packaging can meet the needs of the domestic printing industry. In the coming period, China will greatly increase the quality of pharmaceutical aluminum foil blister packaging to meet the needs of the pharmaceutical market. Therefore, pharmaceutical aluminum foil printing materials for pharmaceutical printing and packaging materials, pharmaceutical aluminum foil printing inks, and adhesives for auxiliary materials, and pharmaceutical polyvinyl chloride materials are currently the pharmaceutical packaging materials with good development prospects in the printing of flexible packaging products. Based on the present situation of the use of aluminum foils, printing inks, adhesives and PVC in China, the development trend of pharmaceutical printing blister packaging materials in the future will be discussed. First, the status of medicinal aluminum foil printing ink materials The current market has a wide range of printing inks, brand name, but from the pharmaceutical aluminum foil printing process and the special requirements of pharmaceutical packaging, its printing ink must have good adhesion to aluminum foil Adhesive, printed text pattern solid and clear, fast solvent release, good heat resistance, excellent friction resistance, good gloss, non-toxic pigments, no contamination due to migration of chemical components in the ink packaged drugs, practical viscosity should be consistent with Aluminum foil printing process requirements and so on. From the requirements of several aspects to analyze, currently used in aluminum foil printing inks are mainly divided into two categories: The first category: alcohol-soluble polyamide inks. Because polyamide resin has good adhesion to various types of substrates, especially suitable for printing polyolefin films, with good dispersion, good gloss, softness, good abrasion resistance, solvent release and good printing performance, Therefore, the most used is to use a gravure printing ink specially designed for the surface printing of processed films such as LDPE, CPP, and OPP. Because this kind of ink is widely used, anti-blocking, and easy to dry, it is also used for surface printing of medicinal aluminum foil. When this type of ink is printed on aluminum foil, various excellent properties can be exhibited, and the heat-resisting performance can also meet the requirements during the printing and use of aluminum foil. It is currently the most popular type for medicinal aluminum foil printing. However, such inks are not special inks for aluminum foil printing after all. The problem is that ink peeling has occurred during the printing of large areas of aluminum foil. At present, there are domestic ink factory can produce aluminum foil foil gravure table printing special polyamide ink, some users of the use of the situation shows that: the ink is good heat resistance, strong adhesion, 200 °C high temperature heat test, the printed text pattern is still clear and not discoloration. The second type of ink is an aluminum foil special ink based on vinyl chloride, vinyl acetate copolymer resin and acrylic resin. This is a newly developed gravure printing ink, which is characterized by bright color, high concentration, particularly strong adhesion to aluminum foil, good transparency, and excellent reproducibility of aluminum foil. However, due to the ink in the gravure printing, the volatility of the solvent is large. When the aluminum foil is used for printing, it is easy to cause the gravure roll ink to cause the ink dry knot to produce a paste type phenomenon, which affects the printing quality. The above two kinds of inks are insufficient when used for printing on the surface of pharmaceutical aluminum foils. If it is to adjust the composition of the mixed solvent of the second type of aluminum foil special ink to meet the needs of aluminum foil surface printing, it will be more applied to the surface printing of aluminum foil. Second, the current situation of the application of packaging materials for pharmaceutical packaging aluminum foil pharmaceutical packaging printing materials aluminum foil, is sealed on the plastic PVC plastic film (PVC) on the sealing material, also known as cover material. Its surface can be printed with colorful text and patterns, and it is printable both on the front and the back. The aluminum foil is made of electrolytic aluminum with a purity of 99% and is made by calendering. It is non-toxic and tasteless, has excellent electrical conductivity and shading, and has extremely high moisture resistance, gas barrier and taste protection. Because aluminum foil has a highly dense metal crystal structure, it can completely block any gas, water vapor and light, and it can protect the packaged object most effectively. In modern packaging, almost all products that require opaque or high-barrier composite materials use aluminum foil as a barrier layer, and therefore are widely used. At present, there is still a considerable gap between the overall quality of pharmaceutical aluminum foil in China and imported aluminum foil. From the current actual situation of the production of several pharmaceutical aluminum foil printing companies, there are mainly the following aspects: 1 The number of pinholes in medical aluminum foil is far from the use requirements. The pinhole degree of aluminum foil is a penetrating defect, which seriously affects the barrier property of aluminum foil, especially for the packaging of medicines. It is easy to make oxygen, water vapor, and light penetrate to reduce the efficacy of the medicine. The quality of medicines is related to human life, and pharmaceutical packaging is a special commodity that protects the performance of medicines. It must not ignore its quality. Pharmaceutical aluminum foil requires no pinholes with a diameter greater than 0.3 mm. Pinholes with a diameter of 0.1-0.3 mm cannot have more than one pinhole per square meter. At present, domestic aluminum foil rarely meets this standard. 2 The thickness of medical aluminum foil is uneven and its tensile strength is low. The uneven thickness of aluminum foil makes it difficult to reach the standard for the amount of adhesive applied in the aluminum foil printing process, which results in a large difference in the amount of coating, thereby affecting the heat-sealing strength of aluminum foil and plastic hard sheet; uneven thickness, low tensile strength, After the tension is applied to the take-up roll, it will cause foil breakage, which is not conducive to the normal printing. These problems require the attention of raw material manufacturers. At present, with the rapid development of pharmaceutical aluminum foil packaging and the continuous remodeling of pharmaceutical aluminum foil printing organizations in China, the development of pharmaceutical aluminum foil packaging has been very rapid, and the amount of pharmaceutical aluminum foil has increased year by year. It is expected that the application of pharmaceutical aluminum foil from 1999 to 2001 The amount will exceed 4,000 tons. Among them, in addition to the outer package printing for pharmaceutical tablets and capsules, it will also be used in a large number of external packaging and printing of injection cartridges. Third, the current situation of the application of polyvinyl chloride materials for pharmaceutical aluminum foil printing is currently used in China is a large number of pharmaceutical polyvinyl chloride (PVC) hard film. Because the drug is sensitive to wet moisture, light transmission, etc., the plastic hard sheet must have good barrier properties against moisture, light, and odor. However, the polyvinyl chloride we use today is not ideal in terms of moisture barrier. Therefore, the use of polyvinylidene dichloride (PVDC) or its composite materials should be promoted in the future. Due to its high polymer density, structural regularity, and high crystallinity, polyvinylidene chloride has extremely strong gas tightness, excellent moisture resistance, and good resistance to oils, chemicals, and solvents, especially to Oxygen, water vapor and carbon dioxide gas in the air have excellent barrier properties. Compared with the same thickness of material, the barrier property of polyvinylidene chloride to oxygen is 1500 times that of polyethylene (PE), 100 times that of polypropylene (PP), 100 times that of polyester (PET), and water blocking Steam and oxygen are also superior to polyvinyl chloride. Polyvinylidene chloride not only has good gas and odor barrier properties, but also its impact strength, tensile strength, durability and other indicators can meet the special requirements of pharmaceutical packaging and printing. It is the development direction of pharmaceutical packaging materials in the future. It is expected that the demand for polyvinyl chloride rigid tablets for pharmaceutical packaging will reach more than 40,000 tons in the coming period to 2001, and gradually adopting new high barrier type materials such as polyvinylidene chloride hard sheets and other plastics. Compound PVC/PVDC/PE, PVDC/OPP/PE, PVC/PE and other composite plastic hard sheets that are protected from light brown color will be widely used in the printing and packaging of pharmaceutical aluminum foils. Fourth, the current situation and development trend of pharmaceutical aluminum foil printing and coating adhesives Pharmaceutical aluminum foil is based on pure aluminum foil for industrial use, the surface of the text pattern printed and coated with protective agent, and on the other side coated with adhesive (Text patterns can also be printed before the adhesive is applied). The purpose of the coating protection agent is to prevent the abrasion of the surface printing ink layer, and at the same time prevent the outer layer ink from contacting with the inner layer adhesive when the aluminum foil is wound up and cause the medicine to be contaminated. The role of the adhesive is to bond the aluminum foil and the plastic hard sheet so that the medicine is sealed. The currently used adhesives are mainly divided into one-component adhesives and two-component adhesives. The composition of one-component adhesives is mainly made of natural rubber or synthetic rubber, and nitrocellulose and acrylic esters. Since the main agent is an elastomer, tackifiers are used as auxiliary agents and are formulated into emulsions with organic solvents. Non-dry, hot melt and a certain degree of adhesive strength. With the increase in the hygienic requirements for pharmaceutical packaging materials, the application of this one-component adhesive has gradually decreased, and more use of two-component polyurethane adhesive. It is mainly composed of a main agent and a curing agent. The main agent generally contains many active hydrogens such as hydroxyl, amino and other substances, and the curing agent is composed of polyisocyanate compounds. When the isocyanate group in the curing agent is in contact with the active hydrogen in the main agent molecule, an addition reaction is automatically performed to generate a urethane structure, which doubles the molecular weight after the main agent and the curing agent are combined with each other. Even cross-linked products with a three-dimensional conformation with a branched chain structure have good resistance to high and low temperatures, resistance to media erosion, and high cohesion. Because the polyurethane molecule contains a large number of polar groups, the dipole moment is large, and it has a great affinity for the adhered material, so it plays a role in binding various materials such as aluminum foil and plastics. In addition, the isocyanate group (-NCO) in the curing agent is a very reactive group that can react with the active hydrogen in the main agent molecule and react with the active hydrogen in the surface material of the adherent material. The chemical bonds act to bridge the adhesive molecules with the material being bonded, resulting in stronger adhesion. Due to the good adhesion of such adhesives, it has been widely used in the printing and compounding of aluminum foil printing, coating, and various plastic films. In the future, the application of aluminum foil printing adhesives will be developed toward a solventless type. Its composition is also a two-component type of polyurethane. The difference is that the main agent and curing agent have higher viscosity at room temperature but still have fluidity. Is a semi-solid matter. When used, the main agent and curing agent are mixed in proportion and placed in a container with a heating and heat retention function. After the temperature is raised, the viscosity is lowered. Then, a gravure roll with a heating and heat retention function is applied to the aluminum foil substrate, and the adhesive does not have to be applied. The drying tunnel is heated and dried because it is free from any solvent and can be directly bonded to another substrate. The use of solvent-free adhesives eliminates the problem of exhaust emissions and eliminates the need for bulky drying and blower exhaust devices in print coating equipment. Foreign countries have adopted such adhesives because of their great importance to environmental protection. ·Editor Li Dan·