Packaging film has green credentials
polyester resin that can be used to make environmentally-friendly,
biodegradable pharmaceutical bottles and blister packs.
Another potential advantage of the resin is that it can prevent moisture ingress without using dessicants, which could lead lower raw material requirements and cost savings.
The company notes that biodegradable polymers have been introduced for a range of packaging applications, but their widespread adoption has been held back because their physical properties have not been suitable for good moulding and quality products.
The most commonly used biodegradable polymers have been aliphatic polyesters, but these have tended to be too soft and sensitive to heat and are liable to tear. A number of researchers have tried to increase the length and molecular weight of the polymer chains - with the target set at 30,000 kilodaltons - to improve these properties, but so far without success.
The new patent describes a polyester resin which has superior physical properties to resolve these limitations.
The resin has an average molecular weight in the 30,000 to 600,000 range, and has the strength to resist tearing and the flexibility to be suitable for injection moulding into a range of pharmaceutical containers, including bottles and blister packs.
Moreover, the polymer allows moisture and carbon dioxide to escape from the packaging, but prevents it coming in from the outside, providing a moisture permeability performance that tops any other biodegradable polymer, according to the patent.
"The biodegradable containers produced according to the present invention keep the contents allow the contents to stay in the original condition without quality deterioration even when exposed to a humid environment," it notes.
