Once you get past the basic types of PET plastics, you get into the modified copolymers—these are PET plastics that have been treated with something that changes its structure. Today, I want to introduce PETG plastic, otherwise known as polyethylene terephthalate - glycol modified.
Despite the similarities in the names, PETG isn't technically in the same family as PET, RPET and APET. While those are all different forms of PET, PETG adds a little something extra: Glycol. So what does the glycol do?
Glycol prevents crystallization in the thermoforming process. Remember, when a thermoforming company tries to mold PET plastics but doesn't have the right experience, the plastic can crystallize and lose all the transparency that makes it so popular. By adding glycol, you take away the material's ability to crystallize and turn hazy, but that isn't the only effect.
Because of the added glycol, PETG has a few distinct advantages over your typical PET plastics:
- It's transparent - great for showcasing products
- It's tougher than PET - more impact and chemical-resistant
- Easier to thermoform than PET - takes crystallizing out of the equation
- Like PET, it can be FDA compliant - PETG is used for many food and medical applications
- Unlike PET, it’s RF sealable
Unfortunately, PETG isn't perfect. It's affected by UV light, so it doesn't always hold up so well when used in long-term outdoor applications. While it's impact-resistant, it also has a soft exterior—it won't necessarily break easily, but it will scratch. It's also a particularly sticky material to work with, so if you purchase from a company that doesn't have much experience working with PETG, the product could be marred by imperfections.
PETG's Best Uses
PETG is an FDA-friendly material, so you're free to use it for a wide variety of applications that are both practical and aesthetic, like:
- Ad & graphic displays
- Protective guards/coatings
- Electronic packages
- Sealed packages
- Medical & pharmaceutical packages
- Medical braces
PETG plastics take finesse and experience to work with, but if you know the best methods of thermoforming like PI does, then you know how effective PETG can be. If you need something strong and versatile, PETG might be the plastic you're looking for!