Symbols hold prominence from their ubiquity. Due to this, markings can become as recognizable as the letter “a.” One such symbol is visible to anyone gulping the last few drops from an upturned water bottle—an equilateral triangle accompanied by a number and abbreviation. This number is a Resin Identification Number, and the abbreviated term represents a polymeric material. Together with a triangle on a plastic product, they form a Resin Identification Code (RIC).
Resin Identification Codes are administered by ASTM International, and their current standard is ASTM D7611/D7611M-20: Standard Practice For Coding Plastic Manufactured Articles For Resin Identification.
Resin Identification Codes (RICs)
Numbered 1-7, Resin Identification Codes are used for the following plastic resins: (1) poly (ethylene terephthalate), (2) high density polyethylene, (3) poly (vinyl chloride), (4) low density polyethylene, (5) polypropylene, (6) polystyrene, and (7) other resins.
Change to ASTM D7611-20
Only one major change was made to ASTM D7611-20, and it concerns the manufactured articles that can have the Resin Identification Number “1” and the Abbreviated Term “PETE” or “PET.” In addition to specific compositions for these plastic articles, this revised section (5.7) specifies the necessary melting peak temperature range when tested in accordance with procedure 10.1 in ASTM D3418-15: Standard Test Method For Transition Temperatures And Enthalpies Of Fusion And Crystallization Of Polymers By Differential Scanning Calorimetry.
Change to ASTM D7611-19
For those who want to keep track of all changes to this standard, the one major change to ASTM D7611-19, the previous edition of this standard, was the addition of Section 6 on the process for adding new numbers.
The ASTM D7611 Standard
In addition to demonstrating the appearance of all 7 of the Resin Identification Codes, including the types, names, and sizes for specific plastic types, ASTM D7611-20 details the significance, use, and additional background information of the RICs.
If you want to learn more about Resin Identification Codes and the ASTM standard, please refer to our post Resin Identification Codes (RICs), as Specified by ASTM D7611.
ASTM D7611/D7611M-20: Standard Practice For Coding Plastic Manufactured Articles For Resin Identification is available on the ANSI Webstore.