In the past, glass bottles were used as containers for beverages. The specific format in each country varied depending on national character, culture, industrial situation, environmental awareness, etc., but generally, after their contents were consumed, glass bottles were returned to the store and a monetary deposit for each container was returned to the customer. Once returned, glass bottles were generally collected, washed, and then reused.
As time went by, and as we sought greater convenience, lightness, and portability, glass bottles were replaced by steel cans, aluminum cans, and PET bottles. Because the companies and shops that provided glass bottles had succeeded in reducing the cost of collecting, washing, and re-using, it appeared that a mutual win–win relationship has been built. However, behind this convenience and cost reduction, a larger and more significant issue may have been overlooked—the heavy burden it placed on the global environment.
In the 1990s, with the aim of reducing waste, many countries enacted regulations promoting returnable containers for beverages, and PET resin and PC (polycarbonate) resin came to be widely used in Europe. However, these resins have problems depending on the contents, which involve special cleaning requirements and also limit which beverages they can contain. PEN resin* is one solution that addresses these problems. This resin is used not only for beverage bottles, but also for tableware for school lunches, cups for business use, and so on due to its high level of safety.
With the present focus on the notion of a recycling-based society, we hope that PEN resin, with its comparative ease of reuse, will continue to receive increased attention.
* Invented by ICI in the United Kingdom in 1945, PEN (polyethylene naphthalate) resin is a thermoplastic polyester resin synthesized by a transesterification/polycondensation reaction of dimethyl 2,6-naphthalenedicarboxylic acid (NDC) and ethylene glycol (EG). Its official nomenclature is polyethylene 2,6-naphthalene carboxylate. Compared to PET (polyethylene terephthalate), which is also a thermoplastic polyester resin, it offers better rigidity, excellent mechanical properties, heat resistance, chemical resistance, gaseous barrier properties, UV shielding properties, and less odor adsorption.