Plastic Materials for Packaging and Label (PVC, PP, PET, PE, BOPP, PS)

Many types of plastic materials are available to produce packaging. When you need to create a design to package your products, you may soon discover that two plastic materials are commonly used: PET and PVC. At Plastic Ingenuity, we have clients ask us which plastic materials prove to be most advantageous for their thermoformed packaging designs. Here, we’ve outlined explanations for these two plastics, as well as which proves to be the most beneficial to help you determine which to use.

PET (Polyester)
is the most expensive, basically weatherproof. Mostly used for outdoor applications, can handle rain or shine.
If you need UV and heat resistance type durability, PET is your choice. Most expensive generally easiest to print on.
PET, or polyethylene terephthalate plastics is one the most widely used plastics for thermoforming. The material is molded into the designated shape, and then dried for increased resistance. The plastic is used to produce food containers, beverage bottles, synthetic fibers and more. PET is the most common plastic for thermoforming packaging designs because of its high-strength barrier that can resist outside tampering or other elements.
The following are the biggest benefits that PET plastic provides:

More versatility—PET plastic can be thermoformed for a variety of applications. Although the material is lightweight, it is still strong enough to withstand outside elements for many applications.
Safer for storing materials, especially food—PET plastic is highly suitable for packaging food items, as well as retail, electronic and other products.
Increased durability —PVC is a rigid plastic that has some durability. Over time, though, the material may break down from exposure to UV rays—something that is not ideal for packaging materials, especially for food or retail designs. PET plastic, however, is designed to withstand UV rays, making it a suitable choice for almost all thermoformed packaging designs.

PVC (Poly Vinyl Chloride / Vinyl)
is mostly used for wall and floor graphics with an indoor application. Cheaper than polyester.
Used for outdoor and signage applications. Bumper stickers and grommetted signs. Mostly "bumper-sticker" type applications for labels. More $$ than BOPPs.
PVC plastic, or polyvinyl chloride, is a rigid plastic designed to withstand harsh impacts and extreme temperatures. The material is most commonly used when creating cables, roofing materials, commercial signage, flooring, faux leather clothing, pipes, hoses and more. PVC plastic is created through suspension polymerization to produce a hard, rigid structure.

PP (Polypropylene)
is a cheaper form of polyester, also mostly used for indoor application

BOPP (Biaxially Oriented Polypropylene)
means the film is stretched to increase tensile strength, etc.
Subset of Polypropylene(PP) - Cheap film. You use this when you need a film (i.e. label may get wet), but you don't need outdoor durability. Cheapest MSI.

PS (Pressure Sensitive)
Any paper or film with adhesive 

PE (Poly Ethylene)
is used a lot of in mold labeling, along with PP. MDO and things like Primax (Brand name of MDO) are good for squeezable or conformable labels (for being placed on a curvy surface or squeeze bottle). 

Source: https://printplanet.com/forum/label-packaging-forum/label-discussion/260221-what-do-the-different-types-of-plastic-based-labels-mean-pvc-pp-pet-etc