“Recycling Codes”- How Resins Relate to the Numerical Symbols
If you have ever looked on the bottom of your plastic water bottle you have probably noticed the triangular symbol that looks like a recycling code. The numerical codes found on plastic products are actually related to the composition of the plastic resin used to manufacture the product.
The 7 Plastic Resin Identification Codes and the Significance of the Symbols
The composition of most of the materials used to make plastic products belong to one of six resin types identified under the Resin Identification Code (RIC) [Mol1] [Mol2]. The RIC is a nationwide plastic resin coding system used to identify the resin content in plastic products.
During the manufacturing process, plastic products are imprinted with a special symbol that looks like a number surrounded by a triangle. This graphic symbol relates to the RIC’s numerical coding system. Numbers 1-6 in correlate to the six common resin types, while the number 7 represents a seventh category, which the RIC labels as “other,” for all materials that cannot be identified by one of the six common resins. The Plastics Industry Trade Association (SPI) created the RIC in 1988 to help recycling programs identify the resin content in plastic waste.
How Plastics are Classified into the Seven Resin Codes
- Polyethylene terephthalate (PET or PETE) -RIC 1:
PET is commonly referred to as polyester. It can be used for plastic bottles and containers, food jars and microwave safe food containers. PET is widely recyclable and accepted by curbside recycling programs. Recycled products made from PET include fiber used for carpeting, filler for bedding fleece jackets and duffle bags.
- High density polyethylene (HDPE)- RIC 2:
Blow molded products made from HDPE include plastic grocery bags, cosmetic containers, milk jugs, cleaning containers and laundry detergent containers. Common injection molded applications are extruded pipe, wire and cable covering. Not all plastics made with HDPE are accepted by curbside recycling programs. Recycled products made from HDPE include containers for non-food household items, motor oil, plastic lumber, piping, buckets and recycling bins.
- Polyvinyl chloride (PVC or vinyl) -RIC 3:
PVC is used for both rigid and flexible applications. Common rigid uses are for packing materials, piping and siding, window frames, fencing, decking and railing. Flexible uses include shrink-wrap, deli meat packaging and medical product packaging, including blood bags. Other flexible applications include carpet backing and flooring. PVC is not accepted by curbside recycling programs. Common products made with recycled PVC are traffic cones, garden hose, gutters, and loose-leaf binders.
- Low density polyethylene (LDPE) -RIC 4:
This resin is often used for manufacturing film due to its properties, such as acid resistance, flexibility and transparency. Other products made from LDPE are container lids, toys, squeezable bottles and other food containers, newspaper, household garbage bags, adhesives and sealants. LDPE is not usually accepted by curbside recycling program. Recycled applications include envelopes, floor tiling, furniture and trash cans.
- Polypropylene (PP) -IC 5:
Common products made with PP are yogurt containers, bottle caps, medicine bottles and fibers. PP is not commonly accepted by curbside recycling programs. Recycled products from PP include automobile signal lights, battery cables, oil funnels, brooms and garden rakes.
- Polystyrene (PS)- RIC 6:
PS can be combined with rubber to make high impact polystyrene (HIPS) a material used for durable packaging. PS is commonly used to manufacture egg cartons, plastic cups and plates, medicine bottles and loose fill foam packaging, or “packing peanuts.” This resin is not accepted by curbside recycling programs. Recycled products made from PS include light switch plates, license plate vanity frames, thermal insulation and thermometers.
- Other- RIC 7:
This code is used for plastics that cannot be categorized as belonging to one of the six resin types. Some products manufactured with this code include oven-baking bags and custom packaging. Recycled items include applications for plastic lumber and bottles.
The American Chemistry Council (ACC) publication, Plastics Resin Codes, offers more detailed information on the RIC classification system, including descriptions properties, applications and recycled products commonly made from each resin.
Plastic Coding as a Global Standard and the D7611
Efforts of the American Society for Testing and Materials (ASTM) have expanded the RIC into a globally recognized standard coding system. In 2010 the ATSM issued D7611 – Standard Practice for Coding Plastic Manufactured Articles for Resin Identification. Although the coding system was developed to support recycling efforts nationwide, the codes are not solely for waste management purposes.
Recent changes to the system include the 2013 redesign of the seven imprinted graphic symbols. The original three-arrow triangle design, a commonly recognized recycling symbol, was replaced with a solid triangle.
According to the ATSM, the graphic was redesigned to better reflect the core mission of the RIC, quality control and resin identification prior to recycling. The D7611 states that:
Resin Identification Codes are not “recycle codes.” The use of a Resin Identification Code on a manufactured plastic article does not imply that the article is recycled or that there are systems in place to effectively process the article for reclamation or re-use. The term “recyclable” or other environmental claims shall not be placed in proximity to the Code.
Microdyne Plastics complies with the most current guidelines for responsible manufacturing practices. That is just one of the ways we have been committed to providing quality services to our customers for over 40 years. Are you ready to learn more about our competitively priced, headache free injection and blow molding services can help you with your next project? To get in touch with us, please visit our contact page.
References
SPI Resin Identification Code – Guide to Correct Use https://www.plasticsindustry.org/AboutPlastics/content.cfm?ItemNumber=823&navItemNumber=2144
“Standard Practice for Coding Plastic Manufactured Articles for Resin Identification”http://www.astm.org/Standards/D7611.htm
Plastic Packaging Resins http://plastics.americanchemistry.com/Education-Resources/Plastics-101/Plastics-Resin-Codes-PDF.pdf
