Rigid Plastic Packaging (non-PET)

Introduction

Rigid Non-PET

This Guide addresses high-density polyethylene (HDPE), polypropylene (PP) and polystyrene (PS).  Each material offers unique properties, and plays an important role in the food sector.

High Density Polyethylene (HDPE)

In its Design Guide the Association of Plastic Recyclers (APR) notes that, due to its toughness, natural UV barrier properties and chemical resistance HDPE is one of the most widely used packaging resins, easily converted into a bottle, canister, pail, tub, squeeze tube or closure.

There is high demand for natural recycled HDPE, even for applications that will be made opaque and colored, since the natural material is more conducive to adding color.

Polypropylene (PP)

APR notes that due to its balance of impact, heat and chemical resistance, along with stiffness and close dimensional tolerance, PP is also a widely used packaging resin, and easily converted into a bottle, canister, pail, squeeze tube, tray, tub or closure. Unlike some other polymers, the versatility of PP allows all components (label, body and closure) of many PP packages to be made of PP, which is, in turn, beneficial to recycling.

As noted by the Polypropylene Recycling Coalition:

“PP is used in an array of food packaging and has largely been collected in curbside programs and sorted in Materials Recovery Facilities (MRFs) under the broad category of “3-7” resins.

Most MRF-specific resin sorting capacity is focused on PET and HDPE, which are presumed to be available in higher quantities than polypropylene in the household stream.”

Polystyrene (PS)

Rigid polystyrene (PS) is typically used in applications (e.g., yoghurt pots) requiring its stiffness, resistance to cracking, and ease of modification. The light bulk density of expanded polystyrene (EPS) provides outstanding insulation and cushioning (e.g., meat trays).

A large quantity of polystyrene is not recycled for many reasons. EPS presents challenges related to transportation costs, and PS is often contaminated. In Canada PS remains widely accepted for collection, but actual recycling rates are very low for EPS and low for PS. In the United States PS does not currently meet the collection accessibility criteria established in APR’s definition of recyclable, or by the Federal Trade Commission’s Green Guides. That said, EPS is a very recyclable material: as APR notes, collection and transportation challenges should not be confused with processability and reusability of this material: see the Foam Recycling Coalition.

PS presents a conundrum.  Some life cycle assessments (LCA), like this comparative study of meat trays, show PS as a preferred material.  Furthermore, Canada has several emerging advanced recycling solutions for PS, some with support from the Government of Canada.  However, the Golden Design Rules (GDRs) for plastic packaging call for “no EPS or PS”,  and recent proposed provincial legislation appears headed in the same direction. 

Rigid non-PET Packaging Types

1. High-density polyethylene (HDPE)
2. Polypropylene (PP)
3. Polystyrene (PS)