Blister packaging is a form of plastic packaging that is used for small consumer goods and pharmaceuticals. It is mostly made from thermoformed plastics. Blister packs have a backing of paperboard, aluminium foil, or even other plastic sheets.
Blister packaging, commonly known as unit dose packaging, is used in the pharmaceutical industry for packaging medicine. In blister packaging, a plastic sheet is thermoformed to form multiple cups or blisters that hold the product. Blister packaging is used in multiple areas and not just pharmaceuticals. Blister packs are low-cost packaging that is theft deterrent, tamper evident and provides good protection.
Blister packaging is made from different types of polymers, such as PVC, PVDC, PCTFE, COP, and a few others.#PVCPVC or polyvinyl chloride is the most common blister packaging material. The main advantage of using PVC is the low cost. PVC sheets of 0.25 to 0.3mm are used for making blister packs. #PVDCPVDC or polyvinylidene chloride is used along with PVC sheets to improve the barrier properties of the packaging. This provides excellent protection from oxygen and moisture. #PCTFEPolychlorotrifluoroethylene or PCTFE is another form of laminate for blister packaging. PCFTE is primarily used as a moisture barrier. Compared to all the polymers, PCFTE comes with the minimum value of water vapour permeation. #COPCOP or Cyclic olefin polymers as well as Cyclic olefin copolymers improves the thermoforming in blister packs and even provides good barrier properties. COP, when used with other polymers such as polypropylene and polyethene, allows manufacturers to make blister packs with deep pockets. These are essential for packing medicines. Blister packaging manufacturers also use cold form packaging made from PVC, aluminium, and Polyamide.The notable physical properties of blister packs are as follows:
Blister packs come in multiple types. These are:
Thermoformed blister packs are the most common. The thermoformable blister packaging process involves heating a sheet of plastic or polymer to a temperature where it can be formed using a mold. Thermoformed blister trays are used in medicine and food packaging.[caption id="attachment_9344" align="aligncenter" width="1024"]
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In this form of packaging, a formed plastic sheet having the shape of the product is heat sealed to a paperboard. A full-face seal blister has the plastic packaging from edge to edge of the packaging.[caption id="attachment_9430" align="aligncenter" width="700"]
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This type of packaging uses a single thermoformed sheet trapped inside die-cut cardboard. No sealing tools are required for this.[caption id="attachment_9345" align="aligncenter" width="1023"]
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Here, the blister extends on all sides and wraps around the paper lid.[caption id="attachment_9342" align="aligncenter" width="1024"]
Image Courtesy: pocketsized.org[/caption]
Clamshell is a form of packaging that uses a hinged thermoformed sheet of plastic. This is generally used to pack heavier goods. This type of blister packaging can be reused. A two-piece clamshell is also available that uses two plastic sheets instead of a hinge. A tri-fold clamshell has a bottom stand that allows products to stand upright on store shelves.[caption id="attachment_9340" align="aligncenter" width="1024"]
Image Courtesy: china-clamshell.com[/caption]
This manufacturing technique uses heating and vacuum to form the blisters. The products themselves are used as the molds. The product is sandwiched between heated plastic sheets and the air in the middle part is vacuumed.[caption id="attachment_9343" align="aligncenter" width="1024"]
Image Courtesy: packworld.com[/caption]
Blister packaging is used extensively in multiple industries. Pharmaceuticals and food industry use it mostly. But it is also used for packing electronics, home improvement tools, stationery and more.
In spite of having numerous advantages as a low-cost packaging solution as mentioned before, poorly implemented blister packaging has often caused wrap rage. Blister packaging requires a proper sealing tool for heat sealing the package. Metalized plastic sheets used for certain this type of packaging are hard to recycle. Moreover, how effective the protection of a blister packaging will depend a lot on the backing that is used.