First, the characteristics of pharmaceutical blister packaging and materials
In pharmaceutical packaging, blister packs are the most widely used ideal packaging method. It is the placement of drugs in the recesses (called blisters or blisters) of plastic molded plastic hard disks, followed by a sheet of aluminum foil that has been gravure printed and coated with a protective agent and adhesive, and the plastic. The hard film is heat-sealed to make the medicine safe. Pharmaceutical blister packaging began to emerge from Europe in the 1930s. China began to introduce technology, equipment and raw materials in the 1980s. It began with monochrome printing, and gradually developed into multi-color and color series printing. Blister packs are widely used, are the fastest-growing flexible packaging materials in recent years, and are also the main packaging forms for food, health care products, pharmaceuticals and other fields. The main materials for blister packs are pharmaceutical PTP aluminum foil, plastic hard sheets (PVC PVC) and adhesives.
1. Medicinal PTP aluminum foil
Medicinal PTP aluminum foil is a sealing material that is sealed on a plastic hard plastic sheet and is usually called a cover material. Its surface can be printed with text or pattern, and both sides have good printing application performance. Aluminum foil is made of 99% electrolytic aluminum, and is made by calendering and other processing methods. It is non-toxic and odorless. It has excellent electrical conductivity and light-shielding properties as well as extremely high moisture resistance and gas barrier properties. In modern packaging, almost all require shade or high barrier composite flexible packaging materials. Use aluminum foil as a barrier material. This is because aluminum foil has a highly dense metal crystal structure that can completely block any gas.
2. Plastic hard film
The most commonly used plastic hard piece in PTP aluminum-plastic blister packaging is PVC hard film (abbreviated as PVC hard piece). Although PVC has many advantages such as high quality and low price, it is resistant to moisture, mildew, water vapor, and oxidation resistance. Other aspects are still not satisfactory. And in the production or use of PVC, there has been a long-term impact on the environment and organisms. The main problem lies in the polymerization of PVC monomers, such as vinyl chloride monomers in the preparation of PVC plastic additives such as plasticizers, stabilizers and so on. Incineration of PVC products such as dioxin hydrochloride. As the HC1 generated after the decomposition of PVC has a certain impact on the environment, its monomers, plasticizers, stabilizers are harmful to the human body. At present, foreign developed countries have already banned and restricted the use of PVC as a blister pack. New blister-packed plastic sheets must be non-toxic and have good water-repellency and oxygen barrier properties to ensure that medicines will not be effective for a longer period of time. Oxidation, moisture absorption, mildew, deterioration, etc., especially for Chinese medicine, are particularly sensitive. In order to improve the defects of PVC, the production of PVC composite films has begun. This kind of composite sheet is mainly composed of PVC hard film and another kind or new polymer film and sheet. It is also a novel combination material that meets the requirements of pharmaceutical packaging and is produced through extrusion, compounding, coating and other processing methods. Such as PVC and PVDC compound, PVC and PE compound, PVC/PE/PVDC compound. It combines the rigidity of PVC hard film, good molding and excellent barrier properties against vapor, oxygen, carbon dioxide gas and various odors, and can meet the packaging requirements of easily deliquescent, easily oxidized drugs and some traditional Chinese medicines that need to retain odor. At the same time, the use of these composite rigid sheets still follows the original aluminum-plastic blister package, packaging equipment and processes.
3. Adhesive
For blister packaging adhesives, early adhesives were made of one-component pressure-sensitive adhesives. The main components of pressure-sensitive adhesives included synthetic resin adhesives (including natural rubber, synthetic rubbers, celluloses, and polyacrylates). Etc.), Adhesives (including rosin, rosin esters, various petroleum resins, epoxy resins, or phenolic resins, etc.), plasticizers (including chlorinated paraffins, benzene-bis: formic acid, etc.), antioxidants, stabilizers, etc. Agents, crosslinkers, colorants and fillers. At present, pressure-sensitive adhesives for pharmaceutical flexible packaging composites have been replaced by polyurethane adhesives, mainly ester-soluble polyurethane adhesives. Such adhesives are two-component ester-soluble adhesives whose main agent is a polyether or polyester polyol modified aromatic isocyanate, a hydroxyl-containing polyurethane polyol, and a curing agent is a combination of aromatic isocyanate and trimethylolpropane. These adhesives have excellent performance, mature technology, and many varieties, but they are toxic, costly, and emit large amounts of solvents that pollute the environment. The alcohol-soluble polyurethane adhesive is based on industrial alcohol as a solvent, has a low production cost, has good hygienic properties, is harmless to humans, and has no pollution to the environment. The disadvantage is that it is not resistant to high temperatures of 100°C and cannot be packaged with highly corrosive products. Another type of adhesive is an aqueous polyurethane adhesive based on water-soluble or water-dispersible solvents. Its advantage is that water replaces organic solvents. There is no danger of burning and the cost is low. However, poor adhesive properties.