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SPI Resin Identification Codes Explained (1 to 7 Guide)

Key Takeaway: SPI resin identification codes (1 through 7) are standard symbols molded onto plastic products to identify polymer types for post-consumer recycling. Standardized mold inserts ensure crisp, durable markings compliant with ASTM D7611 regulations.

Overview of SPI Resin Codes 1 through 7

Introduced in 1988 by the Society of the Plastics Industry (SPI) and updated under ASTM D7611, the Resin Identification Code system uses numbers 1 to 7 enclosed inside a chasing arrows symbol or solid equilateral triangle.

  • #1 PET / PETE (Polyethylene Terephthalate): Soft drink bottles, water bottles, peanut butter jars.
  • #2 HDPE (High-Density Polyethylene): Milk jugs, detergent bottles, bleach containers.
  • #3 PVC (Polyvinyl Chloride): Plumbing pipes, window frames, medical tubing.
  • #4 LDPE (Low-Density Polyethylene): Squeeze bottles, shopping bags, wire insulation.
  • #5 PP (Polypropylene): Yogurt containers, automotive trim, bottle caps.
  • #6 PS (Polystyrene): Disposable cutlery, foam cups, egg cartons.
  • #7 OTHER (O): Acrylic, Polycarbonate, Nylon, and multi-layer resins.

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