What are Resin Identification Codes for Plastic Recycling?

Resin identification codes are a set of symbols visible on plastics for identifying the polymer type used for that particular plastic manufacturing. The resin identification codes serve the purpose of differentiating polymer types for plastic recycling. These codes are also known as Plastic Identification Codes or Plastic ID Codes. The resin identification coding system was developed by the Society of the Plastics Industry (SPI) in 1988. There are total seven groups of plastic polymers each of which has specific properties and a separate plastic identification code. These resin or plastic ID codes are used worldwide by the recycled plastic manufacturers who make their products with the help of plastic recycling machines. Thus, knowing resin identification codes becomes a necessity for all recycled plastic manufacturers.

 

Understanding Symbols of Resin Identification Codes

The resin identification coding system assigns a typical symbol to each of the seven groups of plastic polymers. The symbols used in the plastic ID code consist of arrows that rotate clockwise to form a rounded triangle and enclose a number. There is also an acronym below the triangle that represents the plastic. For example, Low-Density Polyethylene is written as "LDPE". When the number is omitted, the symbol is called the Universal Recycling Symbol, indicating generic recyclable materials. In such a case, other text and labels are used to indicate the material(s) used. There are some misconceptions about the number shown in the symbols representing plastic identification codes such as these numbers indicate how hard the item is to recycle or how often the plastic was recycled. However, there is no other meaning of the numbers shown in resin identification codes symbols other than that they identify the specific plastic (these numbers have been arbitrarily assigned to the plastics by the SPI). The Unicode character encoding standard includes the resin identification codes, between code points U+2673 and U+2679 inclusive. The generic material recycling symbol is encoded as code point U+267A.

 

Application of Resin Identification Codes Symbols

The Plastic Identification Codes symbol is used to indicate whether the plastic can be recycled into new products. Plastic products manufacturers are required to use PIC labels in some countries/regions of the world. The plastic manufacturers in other parts of the world, where there are no such requirements, can voluntarily mark their products with the plastic identification code. Consumers can easily identify the plastic types based on the codes generally found at the base or at the side of the plastic products that may include food packaging, chemical or pharmaceutical packaging, and containers etc. The PIC is generally not present on packaging films, as it is not practical to collect and recycle most of this type of plastic waste.

 

List of Resin Identification Codes Symbols

Here are the seven resin identification codes for plastic recycling with their symbols and a brief description.

 

Polyethylene Terephthalate (PET, PETE) - Properties include clarity, strength, toughness, barrier to gas and moisture, resistance to heat.

 

High Density Polyethylene (HDPE) - Properties include stiffness, strength, toughness, resistance to chemicals and moisture, permeability to gas, ease of processing, and ease of forming.

 

Vinyl (Polyvinyl Chloride or PVC) - Properties include versatility, clarity, ease of blending, strength, toughness, resistance to grease, oil and chemicals.

 

Low Density Polyethylene (LDPE) - Properties include ease of processing, strength, toughness, flexibility, ease of sealing, barrier to moisture.

 

Polypropylene (PP) - Properties include strength, toughness, resistance to heat, chemicals, grease and oil, versatile, barrier to moisture.

 

Polystyrene (PS) - Properties include versatility, insulation, clarity, easily formed

 

Other - Use of this resin identification code indicates that the plastic product is made with a resin other than the six listed above, or is made of more than one resin listed above, and used in a multi-layer combination. Properties are dependent on resin or combination of resins

All of the plastic products carrying one of the above listed plastic identification codes can be used for making recycled plastic products.