Signage aluminum foil printing material application

Abstract : This paper discusses the performance and application status of pharmaceutical aluminum foil printing materials, and analyzes the development trend of aluminum foil materials in the future.

Pharmaceutical foil printing and blister packaging emerged in Europe in the 1930s. The application of aluminum foil as printing material in China in the 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 color and gold series pharmaceutical packaging aluminum foil products. The printing materials provided by pharmaceutical packaging companies can meet the needs of the domestic printing industry with the use of inks and adhesives for aluminum foil and aluminum foil. 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 used in pharmaceutical printing and packaging materials, pharmaceutical aluminum foil printing inks, 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 pharmaceutical aluminum foil printing ink materials The current market a wide range of printing inks, brands vary, but from the pharmaceutical aluminum foil printing process and pharmaceutical packaging to consider the special requirements, the printing ink must have good adhesion to the aluminum foil Adhesive, printed text pattern solid and clear, fast solvent release, good heat resistance, excellent friction resistance, good luster, non-toxic pigments, no pollution due to migration of chemical components contained in the packaged drug, practical viscosity Aluminum foil printing process requirements and so on. From the requirements of several aspects to analyze, the current application of aluminum foil printing ink is divided into two major categories:
The first category is alcohol-soluble polyamide inks. Because the polyamide resin has good adhesion to the type of printing materials, especially suitable for printing polyolefin film, with good dispersion, good gloss, softness, good abrasion resistance, solvent release and printing performance, so The most used is the gravure printing ink used for printing on the surface of films treated with LDPE, CPP, and OPP. Because this kind of ink is widely used, anti-blocking, and easy to dry, it is also used for the surface printing of medicinal aluminum foil. When this type of ink is printed on aluminum foil, various excellent properties can be surfaced, and the heat resistance can also meet the requirements during the printing and use of aluminum foil. It is currently the most widely used type of medicinal aluminum foil printing. However, such inks are not special inks for aluminum foil stamping after all, and there have been problems with ink peeling when printing on a large surface area of ​​aluminum foil. At present, domestic ink factory can produce aluminum foil special gravure table printing polyamide ink, some users use shows that: the ink heat resistance, good adhesion, 200 °C high temperature heat test, the printed text pattern is still clear and does not change color.
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 can easily cause gravure printing of the ink in the gravure roll ink hole to affect 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 printing foil foil for pharmaceutical packaging The foil packaging material for pharmaceutical packaging is a sealing material sealed on medical plastic PVC (polyvinyl chloride) (PVC) hard sheet, 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 several pharmaceutical foil printing enterprises, there are mainly the following problems:
(1) The number of pin holes in medicinal aluminum foil is far from the use requirement. 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 and 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) Pharmaceutical aluminum foils have uneven thickness and low tensile strength. 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, which in turn affects 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 machinery in China, the development of pharmaceutical aluminum foil packaging is very rapid, with the exception of pharmaceutical tablet capsules. In addition to packaging and printing, 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 China's current application of a larger volume is a pharmaceutical polyvinyl chloride (PVC) hard film. Because the drug is sensitive to wet moisture, light transmission, etc., the plastic hard film must have good barrier properties against moisture, light, and odor. However, polyvinyl chloride used in China is not ideal in terms of moisture barrier. Therefore, in the coming period, polyvinylidene dichloride (PVDC) or its composite materials should be promoted. 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 gases 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 is not only good for gas and odor blocking, but also the impact strength, tensile strength, durability and other indicators of the seal 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 in China will reach over 60,000 tons in the coming period to 2002, and gradually adopting new high-barrier materials such as polyvinylidene chloride hard sheets and other plastics. Complex PVC/PVDC/PE, PVDC/OPP/PE, PVC/PE and other light-colored composite plastic hard films will be widely used in the printing and packaging of pharmaceutical aluminum foil.

Fourth, the current situation and development trend of pharmaceutical aluminum foil printing and coating adhesives Pharmaceutical aluminum foil is based on industrial pure aluminum foil as the substrate, the text pattern is printed on the surface and divided by the protective agent, and the adhesive is coated on the other side. (Text patterns can also be printed before the adhesive is applied). The purpose of the coating protection agent is to prevent the surface printing ink layer from being worn, and at the same time, to prevent the aluminum foil from contacting the outer layer ink and the inner layer adhesive when rewinding to cause the drug to be contaminated. The role of the adhesive is to bond the aluminum foil with 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 components of one-component adhesives are mainly made of natural rubber, nitrocellulose, and acrylic esters. Since the main agent is an elastomer, it is also used as an auxiliary agent to make emulsions with organic solvents. Dry, hot melt and a certain bond strength. With the increase in the hygienic requirements for pharmaceutical packaging materials, the application of this one-component adhesive has gradually decreased, and more two-component polyurethane adhesives have been used. 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 comes into contact with the active hydrogen in the main agent molecule, an addition reaction is automatically performed. The urethane structure is formed, and the molecular weight after the main agent and the curing agent are combined increases exponentially, and the radical is formed into a crosslinked product with a three-dimensional conformation with a branched structure, and has good resistance to high and low temperatures, resistance to media erosion, and stickiness. High-end features. Because the polyurethane molecules contain a large number of polar groups, the dipole moment is large, and there is a great affinity for the adhered materials, so the aluminum foil, plastics and other printing materials play a role in adhesion. In addition, the isocyanate group (-NCO) in the curing agent is a very reactive group that can react with the active hydrogen in the test molecule to form a chemical bond, bridging the adhesive molecule with the material to be bonded. Effect, produce stronger adhesion. Due to the good adhesion of such adhesives, printing and compounding of aluminum foil printing, coating, and plastic films of various types have been widely used.

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. A semi-curing agent is mixed in proportion to the gravure roll with heating and heat preservation function and coated on the aluminum foil substrate. After the glue is applied, it does not need to be heated and dried in the drying tunnel. Because there is no solvent, it can be directly bonded to another substrate. . The use of solvent-free adhesives eliminates the need for exhaust emissions and eliminates the need for large drying tunnels for drying and blowing air in print coating equipment. Foreign countries have adopted such adhesives because of their great importance to environmental protection.

Source: Wujiang Golden Eagle Copper Sign Factory