To facilitate the manual sorting of plastic packages and products for recycling, various methodologies have been developed to place an identifying mark on the package or product to identify the type of plastic. In practice, the development of fast automated sorting of plastic bottles and rapid flake sorting of commodity and engineering plastics has limited the value of these types of markings. Nevertheless, since some curbside bottle collection programs still accept some but not all types of plastics, consumers often rely on the markings to help separate out "acceptable" from "nonacceptable" packages. In commercial operations, time is money, and taking the time to examine an individual plastic bottle to find the plastic resin identifying mark is expensive. In the case of PET soft drink bottles and many pigmented and unpigmented high-density polyethylene bottles, simple sorting by bottle type provides sufficient resin purity for downstream plastics recycling operations.
Four organizations have developed and publicized marking systems for plastic packages and products (Table 14.5). The original chasing arrow system developed by The Society of the Plastics Industry (Washington, DC) covers seven plastic resin categories and was developed for the marking of plastic bottles only. In practice the chasing arrow symbol is often found on plastic film and other products. It is still widely used to mark bottles, jars, and containers in the United States. The system (Fig. 14.5) covers the six principal resins used in packaging applications: polyethylene terephthalate (PETE or PET), high-density polyethylene (HDPE), polyvinyl chloride (V), low-density polyethylene (LDPE/LLDPE),
Figure 14.4. Markets for scrap tires and rubber derived from scrap tires. (Source: Rubber Manufacturers Association.)
Table 14.5 Plastic Marking Guidelines and Standards
Guideline/Standard Responsible Organization
Technical Bulletin RPCD-13-1989 Society of the
Revision 1 Voluntary Guidelines Rigid Container Material
Code System Mold Modification Drawings
Surface Vehicle Recommended SAE International
Practice SAE J1344
Marking of Plastic Parts
International Standard ISO International
1043-1 Organization for
Plastics—Symbols and Standardization (ISO)
abbreviated terms—Part 1: Basic polymers and their special characteristics
International Standard ISO 1043-2
Was this article helpful?
You Might Just End Up Spending More Time In Planning Your Greenhouse Than Your Home Don’t Blame Us If Your Wife Gets Mad. Don't Be A Conventional Greenhouse Dreamer! Come Out Of The Mould, Build Your Own And Let Your Greenhouse Give A Better Yield Than Any Other In Town! Discover How You Can Start Your Own Greenhouse With Healthier Plants… Anytime Of The Year!