Should I use PET or HDPE for my bottle?

PET for clear, pressurised or premium products (water, CSD, juice, oil); HDPE for opaque, light-sensitive or chemical products (milk, detergent, bleach).

Why is milk usually packaged in HDPE, not PET?

HDPE is opaque, protecting milk from light, and is flexible and low-cost; PET can also do milk, often with an opaque white additive for ESL or longer shelf life.

Can HDPE hold carbonated drinks?

No — HDPE cannot hold CO₂ pressure; carbonated soft drinks need PET (typically a PCO 1881 neck).

PET vs HDPE for Bottles: Which Plastic and When

Q: Which is more recyclable, PET or HDPE?

Both are widely recycled — PET is resin code 1, HDPE code 2. PET recycles bottle-to-bottle into food-grade rPET; HDPE usually into non-food products.

Q: How are PET and HDPE bottles made differently?

PET is stretch-blow-moulded from an injection-moulded preform; HDPE is usually extrusion-blow-moulded directly from resin — so PET buyers purchase a preform, HDPE buyers blow from resin.

PET and HDPE are the two workhorse bottle plastics — and they win on different jobs. PET is clear, strong and holds pressure; HDPE is opaque, chemical-resistant and squeezable. Here is an honest comparison to pick the right one.

At a glance

Property	PET	HDPE
Clarity	Clear, glass-like	Opaque / translucent
Process	Stretch-blow from a preform	Extrusion-blow from resin
Holds CO₂ pressure	Yes (CSD)	No
Chemical resistance	Good	Excellent (detergent, bleach)
Light protection	Needs an additive	Inherent (opaque)
Feel	Rigid	Flexible / squeezable
Recyclability	Bottle-to-bottle, food-grade rPET (code 1)	Widely recycled (code 2), usually non-food
Typical use	Water, CSD, juice, oil, clear packs	Milk, detergent, chemicals, opaque packs

Clarity and shelf appeal

PET is glass-clear, so it suits products that sell on visible contents — water, juice, oil. HDPE is opaque; that is a drawback for clarity but an advantage for light-sensitive products that need protection.

Barrier and contents

PET holds carbonation pressure and gives a good oxygen barrier — essential for CSD and shelf-stable drinks. HDPE cannot hold CO₂, but its opacity protects against light and it resists aggressive chemistry (detergents, bleach) better than PET.

Process and format

PET bottles are stretch-blow-moulded from an injection-moulded preform (see how a PET bottle is made) — so PET buyers purchase a preform. HDPE is usually extrusion-blow-moulded directly from resin. Different lines, different supply.

Recyclability

Both recycle widely — PET is resin code 1, HDPE code 2. PET recycles bottle-to-bottle into food-grade rPET; HDPE usually goes into non-food products. Compare on a full life cycle, not the code alone.

How to choose

Water, CSD, juice, edible oil, clear premium → PET.
Milk, detergent, household chemicals, opaque or squeezable → HDPE (PET can do ESL milk with an opaque additive).

Where Delta fits

Delta El Nile for Industry supplies PET preforms across 54 SKUs and HDPE closures — so the cap on your HDPE or PET bottle and the PET preform itself can come from one source. Compare the range or build an RFQ.