If you ever purchased the big plastic bottles of vodka or whiskey on the bottom shelf of your local liquor store, you may have noticed something. No, not the hangovers that pulsate agony in your temples with every beat of your throbbing heart. Something that happens before you get to that point: no proper handles. Some have pinch handles; most of the others, you have to grab around the neck.
This is because such bottles, like your soda bottles, are made with polyethylene terephthalate using a stretch blow molding process:
Here an example of the process that doesn’t yield handles.
Enter Eastman Chemicals' new copolyester, Aspira EN177. Eastman says this resin provides PET-like clarity and gloss. But it can be processed in the kinds of extrusion blow molding machines that make milk jugs and motor oil containers. It thus allows for handles and other features. “Co-polyesters can have the same shelf appeal as glass,” says Sam Glover, Eastman’s market development manager for food and consumer packaging at Eastman.
Here’s an example of extrusion blow molding:
Eastman isn't saying exactly what the polymer exactly is chemically. It is in the same family as its Eastar brand. And generally speaking, Eastman copolyesters are copolymers of purified terephthalic acid or dimethyl terephthalate with a diol.