The identification and selection of an appropriate material for the basic container is only part of the complete package concept. Not only the method of keeping the product inside the container but also how it is to be dispensed means that the selection of a proper closure is as important as selecting the container itself. Since the closure is such a critical part of any package, here are some of the goals needed to achieve:
- Proper seal for the Product shelf life.
- Prevent permeation of the product.
- Prevent attack of the liner system by the product.
- Temperature tolerance - Resistance to melting, or distortion at high temperatures, and embrittlement at low temperatures.
- Resistance to "back-off" or loss of torque in transit, or storage.
- Dispensing convenience, or controlled metering.
- Child resistance to opening in the case of hazardous product.
- Tamper evidence.
- Instructions for use.
- Aesthetics of the package design.
- Supplement the label claim (e.g., new and improved).
Closures are made of tinplate, aluminum, phenolic, urea, polypropylene, polyethylenes, PET, or polystyrene. Each has its special uses which are explained in greater detail under "Materials" in this section.
Liner systems, like closures, are available to meet a wide range of needs and new systems are replacing older ones continuously. Refer to Liner Materials & Systems data in this section.
O. Berk can provide guidance and laboratory testing where required to help bring products to market with integrity, functional convenience and aesthetic appeal.