Know Your Plastic: A Primer on Resin Codes (for industrial use)

When creating or searching for plastic parts for industrial use, the choice of material is important. But with dozens of plastic options to choose from, how do you decide which one is best? Enter resin identification codes (RICs), the system of numbers used to identify plastics, which range from 1 to 7.

At Gemini Plastics Inc., we custom design plastics for industrial use. From machine/equipment covers, trays, housings, enclosures, panels, to structural parts, knowing what each resin can provide allows you to design smarter and perform better in harsh conditions.

♳ 1 – PET (Polyethylene Terephthalate)

Common Industrial Uses: Clear guards, machine covers, electrical housings (in PETG form).

Key Properties:

• Strong and impact-resistant

• Lightweight

• Moderate chemical resistance

• Optical-grade clarity (PETG)

• Simple to fabricate and thermoform

Notes: Ideal for applications where visibility and strength are crucial. PETG is a common modifier’s choice for adding industrial clarity with durability.

♴ 2 – HDPE (High-Density Polyethylene)

Common Industrial Uses: Chemical tanks, industrial liners, cutting boards, wear plates.

Key Properties:

• High chemical resistance

• Low moisture absorption

• High impact strength

• Very low friction surface

Notes: HDPE is used in a wide range of applications and is especially common in piping systems, chemical and food processing, and environmental drainage.

♵ 3 – PVC (Polyvinyl Chloride)

Common Industrial Uses: Pipes, cable insulation, casings, lab equipment.

Key Properties:

• Excellent corrosion and chemical resistance

• Flame retardant (in rigid form)

• Tough under extreme conditions

Notes: Rigid PVC is well-suited for utility covers, ducting, and structural use. It’s not ideal for impact-heavy scenarios unless modified.

♶ 4 – LDPE (Low-Density Polyethylene)

Common Industrial Uses: Flexible tubing, liners, sheeting for light industrial use.

Key Properties:

• Flexible and resilient

• Moisture-resistant

• Good electrical insulation

Notes: LDPE is typically used in non-load-bearing parts or flexible liners and membranes.

♷ 5 – PP (Polypropylene)

Common Industrial Uses: Automotive components, chemical tanks, electrical fittings, hinge mechanisms.

Key Properties:

• Excellent fatigue resistance

• Good chemical and moisture resistance

• High melting point

Notes: Perfect for living hinges and heat-exposed parts. Often chosen for its low cost and chemical resistance.

♸ 6 – PS (Polystyrene)

Common Industrial Uses: Rarely used in industry unless blended (e.g., ABS blends).

Key Properties:

• Brittle and rigid

• Low impact resistance

• Easy to mold

Notes: Not commonly used on its own in industrial settings. More often replaced by ABS or polycarbonate for practical applications.

♹ 7 – Other / Engineering Plastics

Common Plastics in This Group:

• ABS (Acrylonitrile Butadiene Styrene): Great for enclosures and structural parts.

• Polycarbonate (PC): Excellent impact resistance and clarity.

• Nylon (PA): High strength and wear resistance; good for mechanical parts.

• Acetal (POM): Low friction and dimensional stability, ideal for gears and bearings.

Notes: Most engineering plastics fall into this category. These materials are built for high-performance parts and are central to Gemini Plastics’ offerings.

Selecting the Right Plastic for Your Industrial Needs

Consider the following when choosing a resin:

• Load and impact resistance

• Environmental exposure (chemicals, UV, temperature)

• Machinability or formability

• Durability and long-term wear

• Cost vs. performance

At Gemini Plastics Inc., we work with our clients to choose the right plastic for the job. Whether you're developing OEM parts, industrial automation tools, or custom enclosures, we make sure the material fits your exact needs.

Can’t Decide on a Plastic? Let’s Chat.

With over 30 years of experience in custom plastic manufacturing, we’ll help you select the ideal material, tooling, and production method to meet your specs and stay on budget.

👉 Contact Gemini Plastics Inc. today to get started on your next industrial project.