Packaging Materials Guide: PET vs HDPE vs PP vs Glass
Material choice affects compatibility with your product, shelf appearance, cost, weight, and recyclability. This guide covers the most common packaging materials and when to use each — written for buyers, not material scientists.
PET — Polyethylene Terephthalate
Resin code #1Clear, lightweight, recyclable
PET is the clearest of the common plastic resins — it has a glass-like clarity that makes products look premium on a shelf. It’s lightweight, shatter-resistant, and widely accepted by recycling programs (it’s what most beverage bottles are made from).
Best for:
- Beverages and water
- Personal care (shampoo, lotion)
- Salad dressing, condiments
- Vitamins and supplements
- Anything where clarity matters
Limitations:
- Not for hot-fill above ~160°F
- Poor resistance to ketones and strong acids
- Can absorb odors from certain products
China sourcing note: Specify food-grade vs. industrial grade — the additive packages differ. rPET is widely available from Chinese bottle suppliers.
HDPE — High-Density Polyethylene
Resin code #2The workhorse plastic — chemical resistant, opaque
HDPE is the most widely used material in packaging. It’s rigid, impact-resistant, chemically inert to most aqueous solutions, and naturally translucent (milky white in natural color). It’s the standard for pharmaceutical, industrial, and household chemical bottles.
Best for:
- Pharmaceutical and supplement bottles
- Cleaning products and detergents
- Industrial chemicals
- Milk jugs and dairy
- Shampoo in opaque formats
Limitations:
- Opaque — not suitable where clarity matters
- Permeable to some aromatic hydrocarbons
- Not for hot-fill above 180°F
China sourcing note:Specify “food-grade HDPE” or “pharma-grade HDPE” explicitly — additive packages differ. Colors are achievable with masterbatch pigment; get a physical sample approved before production.
PP — Polypropylene
Resin code #5Heat-resistant, standard for caps and hot-fill
PP is the go-to material when heat resistance is needed. It withstands temperatures up to 275°F (135°C), making it suitable for hot-fill applications, autoclave sterilization, and microwave-safe containers. PP is also the standard material for nearly all plastic caps and closures — most continuous thread caps you encounter are PP.
Best for:
- Hot-fill products (sauces, honey, soups)
- Microwave-safe containers
- Caps and closures (nearly universal)
- Medical and lab containers
Limitations:
- Less clear than PET
- Brittle at very cold temperatures
- Susceptible to UV degradation without inhibitors
LDPE — Low-Density Polyethylene
Resin code #4Flexible, squeezable
LDPE is a softer, more flexible version of polyethylene used when the container needs to flex. It’s the standard for squeeze bottles, dropper bottles, and tube-style containers. Chemical resistance is similar to HDPE but rigidity is much lower. Natural LDPE is translucent, not optically clear.
Best for:
- Squeeze bottles (condiments, craft glue, honey bears)
- Eye drop and dropper bottles
- Lab wash bottles
- Any product dispensed by squeezing
Glass
Premium / inertInert, premium perception, heavy
Glass is chemically inert — it doesn’t interact with its contents, leach plasticizers, or absorb odors. That inertness makes it the standard for essential oils, perfumes, pharmaceuticals, and any product where interaction with the container is a concern. Glass also carries a premium perception that plastic rarely matches.
Best for:
- Essential oils and fragrance
- Pharmaceutical liquids
- Premium personal care
- Hot sauces and specialty food
- Products marketed as natural/clean
Limitations:
- 2–5× the cost of comparable plastic
- Heavy — significantly adds to shipping cost
- Breaks on impact
- Slower to fill than plastic
Amber vs. clear glass: Amber glass blocks UV radiation, which degrades light-sensitive products like essential oils, certain medications, and some food products. If your product is UV-sensitive, amber glass is a functional requirement, not just an aesthetic one.
Quick Comparison
| Material | Clarity | Heat resist. | Chem. resist. | Cost |
|---|---|---|---|---|
| PET | Excellent | Moderate | Good | $ |
| HDPE | Opaque/translucent | Good | Excellent | $ |
| PP | Fair | Excellent | Good | $ |
| LDPE | Translucent | Poor | Good | $ |
| Glass | Excellent | Excellent | Excellent | $$–$$$ |
China Sourcing Notes
When sourcing packaging from China, always specify the resin grade, not just the material name. “HDPE” without qualification could mean food-grade, industrial-grade, or recycled content — with very different additive packages and regulatory compliance profiles.
- For food or pharmaceutical contact: require FDA-compliant resin and request the Certificate of Analysis (COA) from your supplier.
- For PCR content: specify the percentage explicitly (e.g., “25% PCR HDPE”) and verify with documentation.
- Color matching: get a physical sample approved before production runs. Colors that match on screen can vary significantly without a confirmed Pantone reference.
