Surface Coating Resins
The development of vaccines is not the only step being taken to combat the coronavirus (Covid-19). Existing drugs are being tested and new ones invented too. They include antimalarials, anti-Ebola developments, and treatments for AIDS or rheumatism. Once a drug has been approved, the next step is to produce the active ingredient in sufficient quantity – and to keep it secure and maintain its integrity until it reaches the patient.
Liquid preparations are dispensed under the most stringent safety standards, while formed solid drugs, such as tablets, coated tablets and capsules, are commonly packaged in blister packs. “Hermetically sealed blister packs don’t give germs and humidity a chance,” explains Feike van der Heide, in charge of the resins business at WACKER. With blister packs, it is important for the bond between the aluminum foil and the plastic to be strong while still allowing the pack to be easily opened. That’s where polymeric binders from WACKER come in. “Our VINNOL® surface coating resins have an outstanding adhesion profile for the heat-seal coatings used to join the foil to the plastic in blister packs,” says van der Heide. VINNOL® surface coating resins also possess other qualities that speak to their use in blister packs: they resist water, alcohol and many other chemicals, are odorless and tasteless and will bond to metals and numerous plastics.
Heat-Seal Coating Provides a Protective Barrier
Push-through packs are made by first applying a heat-seal coating to the aluminum and then sealing the coated foil to the plastic film, without the use of adhesive. The heat-seal coating, based on VINNOL® binder, acts as a barrier which keeps the packaged product away from the foil. This principle is also used for sensitive foods. The foil lid on a yogurt tub, for example, is coated with VINNOL® binder for sealing the lid to the tub while preventing the yogurt from coming into contact with the aluminum. The same also applies to processed cheese packaging. Here, the binder enables the thin foil to be sealed at low temperatures and low pressure, extending the shelf life of the cheese, which contains salt, fat and water, and locking in its flavor.
VINNOL® is WACKER’s brand for a system of vinyl chloride copolymer and terpolymer building blocks that serve as binders in numerous solvent-borne coatings applications. Aside from heat-seal coatings for aluminum foil, applications include printing inks and industrial coatings. A range of different polymer resins are available for matching various properties to the intended application. WACKER’s broad product portfolio in this field is founded on more than 60 years of experience.
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WACKER's efforts against coronavirus
VINNOL® surface coating resins keep blister packs airtight and sterile.