A brief yet comprehensive guide for understanding different types of plastics, their class, and how to recycle.

1. STOCKBRIDGE
PLASTICS
Understanding the
Various Types and
Classifications of
Plastics

2. In 1988, the Society of Plastics Industries
(SPI) developed a classification system to
help consumers and manufacturers
properly recycle items based on their
specific class number. This number is
commonly found on the bottom or sides of
plastic containers inside a triangle of
arrows.
As it is our mission at Stockbridge Plastics
to help businesses dispose of their plastics
in efficient and sustainable methods, we
have created a guide to help you
differentiate between the various types of
plastics available.

3. SPI CODE 1 PLASTICS
The classification of plastics that are marked with
the SPI code of 1 are made with polyethylene
terephthalate. This is also referred to as PET/PETE.
Polyethylene terephthalate is known for absorbing
the odors and flavors of whatever it holds.
Therefore, the most common usage for PET/PETE-
based containers is as food storage containers such
as jars and juice bottles. Non food related uses
include bean bags, and combs.
The recycling rate for PET/PETE is around 30%, making it one of the most
common recycled materials. Recycled PET/PETE based products are used
as tote bags, winter weather items, and straps.

4. SPI CODE 2 PLASTICS
The classification of plastics that are marked with
the SPI code of 2 are made with high density
polyethylene. This is also referred to as HDPE
HDPE based products are extremely safe and do not
emit chemicals into foods and beverages. However,
if a container did not originally contain an edible
substance, it should not be re-used to contain
something that will be eaten. HDPE is typically used
to make containers for milk, shampoo, detergents,
and some toys.
Similar to PET/PETE, the recycling rate for HDPE is also around 30%, making it
another commonly recycled material. Recycled HDPE based products are used for
items like crates, fencing, and flower pots.

5. SPI CODE 3 PLASTICS
The classification of plastics that are marked with
the SPI code of 3 are made with polyvinyl
chloride. This is commonly referred to as PVC.
Unlike categories PET/PETE and HDPE, PVC should
never be used to hold edible items. PVC is most
widely known to be used for piping, tiling and
other industrial uses.
Due to its limited usage and difficulty to recycle on an industrial level, PVC
has an extremely low recycling rate. However, Stockbridge plastics does
recycle PVC. Recycled PVC is typically used for decking, paneling, and
garden hoses.

6. SPI CODE 4 PLASTICS
The classification of plastics that are
marked with the SPI code of 4 are made
with low-density polyethylene. This is
commonly referred to as LDPE.
LDPE is extremely flexible, durable, and
not known to release hazardous chemicals.
These properties make its application for
usage endless; however it is most
commonly used as food storage, cling
wrappings, and plastic bags.
The recycling rate for LDPE is low, but it is still recycled. Recycled LDPE is
commonly used for plastic lumber and compost bins.

7. SPI CODE 5 PLASTICS
The classification of plastics that are
marked with the SPI code of 5 are made
with polypropylene, also referred to as PP.
PP is a strong material that can withstand
extreme heat, making it perfect for
microwavable containers. Other common
uses for PP are prescription bottles, boxes,
and plastic caps.
Since PP is often mixed with other types of resins and pigments, it is not
typically recycled, causing a low recycling rate. Once sorted, recycled PP is used
for brooms, battery casing, and ice scrapers.

8. SPI CODE 6 PLASTICS
The classification of plastics that are
marked with the SPI code of 6 are made
with polystyrene. Polystyrene is also known
as PS, but is most commonly referred to as
Styrofoam.
PS has similar uses to products made from
polyethylene; however, PS is stiffer and
more heat resistant. Hot foods and
beverages are better suited for PS based
products. It’s other uses also include
plastic cutlery and packing foam.
Since Styrofoam is often difficult to recycle, it has a very low recycling rate.
Recycled Styrofoam is used for packaging, thermal insulation, and even
license plates.

9. SPI CODE 7 PLASTICS
The classification of plastics that are
marked with the SPI code of 7 are
miscellaneous items that have not been
defined by the previous categories. You
can often find polycarbonate in category 7,
but it is not exclusive to this material.
Since there are hundreds of plastics that
can be placed into class 7, the applications
are endless. Typically, you will find water
bottles, baby bottles, and CDs are made
with Category 7 plastics.
Even though this category encompasses a wide variety of plastics, the
recycling rate is still low. Recycled Category 7 materials are typically used
for plastic lumber.

10. About Stockbridge Plastics
Stockbridge Plastics specializes in providing industrial-
grade green solutions for plastic recycling and grinding.
We recycle of all the plastics listed and do so in a
responsible and sustainable manner. All of our wholesale
plastics and recycled plastics for sale are contamination
free.