Materials · Comparison

PET vs HDPE vs PETG vs PP: How to Choose the Right Plastic Packaging Material

Seven materials, one decision. This page is the factual comparison — what each polymer does, what it refuses to do, and the condition that decides between them.

Quick answer

There is no best packaging material — there is a material that fits four inputs

Any table that ranks plastics from best to worst is answering a question nobody asked. The material is decided by four inputs, in this order: what the formula does to the polymer (pH, surfactants, solvents, alcohol, essential oils), what the shelf has to show (clarity or opacity), the fill temperature, and what the brand has committed to on recycled content. Everything else — capacity, neck finish, decoration — is set afterwards.

So read the tables below as conditions, not as scores. Where a cell says suitable for, that material is a candidate to specify. Where it says consider when, that is the condition that makes the material the right answer. Where it says depends on, the answer is not in the material name at all — it is in the formulation, and it has to be tested.

One rule before the tables

Actual material/formulation compatibility must be validated against the real formula, concentration, temperature, storage conditions and intended use.

This page therefore names candidates to evaluate and the conditions that decide them. It does not declare any material unconditionally safe for any formulation.

Materials molded

2,000+

Stock molds

646

PET bottle molds

427

PE bottle molds

5,000 pcs

MOQ per SKU

3–10 days

Sampling

The comparison

Material comparison table

The six columns below are the six things a buyer actually has to settle. The last column is the condition that decides the choice — if you only read one column, read that one.

Material	Transparency	Chemical resistance	Typical use	Recycling	Key consideration
PET	High, glass-like	Medium — attacked by strong alkali and some oils	Cosmetic, skincare, personal care	Widely accepted (rPET available)	Consider when clarity and rigidity sell the product
HDPE	Opaque	High	Body wash, detergent, cleaning, bulk	Widely accepted	Consider when the fill is aggressive or distribution is rough
PE (LDPE / MDPE)	Translucent	High	Squeeze packs, lotion, shampoo	Widely accepted	Consider when the pack must be squeezed or the fill attacks PET
PETG	Very high, stays clear in thick walls	Medium — sensitive to some oils and alcohols	Premium serum, thick-wall jars	Depends on the collection system	Consider when the brief needs a heavy glass look PET cannot hold
PP	Low to medium, milky	High	Closures, pumps, jars, heat-adjacent packs	Widely accepted	Consider when heat resistance or closure performance leads
PCR PET	Low to medium, grey or green cast	Medium	Non-clear, tinted and opaque packs	Recycled feedstock	Depends on whether your market accepts the colour cast
PCR HDPE	Opaque	High	Cleaning, detergent, industrial	Recycled feedstock	Depends on the recycled-content target your brand has committed to

Nothing in that table is a ranking. PET is not better than HDPE; it is clear and HDPE is not. The useful question is which of the seven refuses your fill, and that is the next table.

Compatibility

Chemical resistance against the fill families we see most

These are starting candidates, not approvals. Environmental stress cracking, absorption into the wall and permeation through it all depend on concentration, contact time, storage temperature and how the pack is stacked. Use this table to narrow the field, then test the real formula.

Fill family	PET	HDPE	PE	PETG	PP	What decides it
Water-based lotions, toners, gels	Suitable for	Suitable for	Suitable for	Suitable for	Suitable for	All five work; appearance decides
Acidic, roughly pH 3–5 (AHA, vitamin C)	Consider when the acid load is low	Suitable for	Suitable for	Depends on the acid	Suitable for	Acid type and concentration, not just pH
Alkaline (soap, ammonia-based cleaners)	Depends on the alkali	Suitable for	Suitable for	Depends on the alkali	Suitable for	Sodium hydroxide attacks PET; polyolefins tolerate it
Alcohol-containing (above 20% ethanol)	Consider when tested	Suitable for	Suitable for	Depends on the alcohol load	Suitable for	Ethanol softens PETG and can stress-crack it under load
Essential oils and fragrance concentrates	Depends on the oil	Suitable for	Suitable for	Depends on the oil — highest risk of the five	Suitable for	Terpene content; always validate by soak test
Oxidising agents (peroxide, hypochlorite)	Depends on the concentration	Depends on the concentration	Depends on the concentration	Depends on the concentration	Depends on the concentration	Oxidising fills are always validated by test, never by material alone
Hot fill above 70 °C	Consider when heat-set specified	Suitable for	Consider when tested	Consider when tested (ceiling around 70–75 °C)	Suitable for	Fill temperature and vacuum compensation, not chemical resistance

Where the cell reads suitable for, that still means "suitable for, pending a test on your actual formula". A compatibility assumption is the most expensive assumption in this table, because it fails in a warehouse three months after the factory has been paid.

Test it rather than assume it

Formula compatibility guide →Packaging testing →

Appearance

Transparency decides more projects than chemistry does

In cosmetics and personal care, most of the material decision is an appearance decision. If the fill has to be seen — a serum, a toner, a gel with suspended particles — the polymer has to be transparent, and that narrows the field to two. If the fill does not have to be seen, opacity costs nothing and buys chemical resistance plus a lower unit cost.

Material	Optical result	How it behaves in thick sections	Suitable for
PET	Clear, glass-like, high gloss	Hazes as the wall thickens — PET is semi-crystalline	Clear bottles and jars where the fill is the product
PETG	Clear, glass-like, thick-wall capable	Stays clear at 3–5 mm, which is the reason it exists	Serum bottles, heavy-base jars, thick-walled premium packs
HDPE	Opaque, dry matt finish	Opaque at any thickness	Cleaning, body wash, detergent, bulk formats
PE (LDPE / MDPE)	Translucent to opaque	Milky white; does not become clear	Squeeze packs and formats where softness reads as quality
PP	Semi-translucent, waxy sheen	Never reaches optical clarity	Caps, pumps, jars, closures and heat-adjacent packs
PCR PET	Grey or green cast, higher haze	Cast deepens as content and wall thickness rise	Opaque or heavily tinted packs with a recycled-content commitment
PCR HDPE	Opaque, slightly warmer grey than virgin	Opaque at any thickness	Cleaning and industrial packs where opacity never mattered

One consequence worth stating plainly: if a brief asks for a thick, completely clear wall, the answer is usually PETG rather than PET — but PETG then limits the formulation, because it is the more solvent-sensitive of the two. That trade is the reason this page exists.

Temperature

Fill temperature and the heat ceiling of each material

Fill temperature is a hard constraint that cannot be decorated around. It changes the resin, the preform, the tooling and the bottle geometry — a hot-filled pack needs vacuum compensation panels, because the internal pressure drop as the contents cool will otherwise pull the side walls in.

Material	Practical fill window	What changes above it
PET	Roughly 60–70 °C	Needs a dedicated heat-set grade, heat-set tooling and a modified preform; some clarity is lost
PETG	Roughly 70–75 °C	Very limited headroom; above it the wall distorts and stress cracking risk rises
HDPE	Roughly 90–110 °C	The highest of the clear-or-opaque pair; the normal answer for hot fill in opaque formats
PE (LDPE / MDPE)	Depends on the grade and wall	Squeeze packs lose recovery as wall temperature rises
PP	Highest of the materials we run	The reference material for closures and heat-adjacent packs
PCR PET / PCR HDPE	Per the base polymer	Recycled content does not raise the ceiling, and PCR PET crystallises slightly differently from virgin

Tell us the fill temperature before we quote. It sits upstream of the specification, so a late change costs a tool rather than a drawing.

Hot fill in detail

Hot-fill packaging rules →Bottle design guide →

Barrier, cost and recycled content

The three secondary specifications

Barrier, cost and recycled content rarely decide the material on their own, but they decide the margin and the marketing claim. They are worth stating separately because they point in different directions from appearance.

Property	PET	HDPE	PE	PETG	PP
Moisture barrier	Good	Very good	Very good	Good	Very good
Oxygen barrier	Moderate	Poor	Poor	Moderate	Poor
Light transmission	High (needs UV blocker if the fill is light-sensitive)	None — opaque	Partial	High	Partial
Relative cost per kg	Baseline	Low	Low	Highest	Low
Recycled-content availability	PCR PET, commonly 30–100%	PCR HDPE available	PCR grades limited	Not a mainstream recycle stream	Recycled grades limited
Effect of recycled content	Grey or green cast, higher haze, small odour risk	Slight colour shift, no optical cost (already opaque)	Small colour shift	Not applicable in practice	Small colour shift

If the brand has committed to a recycled-content figure, that is a specification decision rather than a decoration: set the target, then accept the colour shift the content level brings with it. The evidence to ask for is a transaction certificate naming your product and lot — an annual scope certificate only proves the factory was audited.

Recycled materials in detail

PCR PET →PCR HDPE →

Material by material

Suitable for, and the condition that decides it

One line per material, stated as a condition rather than a verdict.

The seven materials, in one condition each

PET

Suitable for clear, cold-filled cosmetics and personal care, and any pack where shelf appearance is the selling proposition. Consider when you need clarity, rigidity and the lowest cost per unit of the clear options. Depends on the fill staying below roughly 70 °C and away from strong alkali.

HDPE

Suitable for body wash, detergent, cleaning and bulk formats. Consider when the fill is aggressive, the distribution is rough, or stress-crack resistance matters more than appearance. Depends on accepting an opaque pack.

PE (LDPE / MDPE)

Suitable for squeeze packs, lotion and shampoo formats. Consider when the pack must be squeezed and recover, or when the formulation attacks PET. Depends on the density and melt flow index that suit your filling line.

PETG

Suitable for premium serum bottles and thick-wall jars. Consider when the design needs a heavy, glass-like wall that PET would haze. Depends on the formulation: PETG is the most solvent-sensitive of the five primary materials, and it costs the most.

Suitable for caps, pumps, sprayers, jars and heat-adjacent packs. Consider when heat resistance or closure performance leads the specification. Depends on accepting a semi-translucent appearance in bottle formats.

PCR PET

Suitable for non-clear, tinted and opaque packs with a recycled-content commitment. Consider when your market rewards recycled content and accepts the colour cast. Depends on the content level: the higher it goes, the stronger the grey or green cast.

PCR HDPE

Suitable for cleaning, detergent and industrial packs. Consider when the pack was never meant to be clear, so recycled content costs nothing optically. Depends on the recycled-content target and the documentation your customer will ask for.

Common starting points

Two combinations that come up every week

Clear cosmetic bottle

PET first. PETG only if the wall has to be thick and stay clear — and then the formulation has to be checked against PETG’s solvent sensitivity.

Aggressive cleaning formula

HDPE or PE. Both give chemical resistance and stress-crack resistance that PET cannot match, and both are cheaper per kilogram. The cost is opacity.

Pitfalls

Where the decision usually goes wrong

▸Choosing on appearance alone. A clear PET pack specified for a strongly alkaline or solvent-heavy fill passes sampling and then cracks in storage. Appearance is the second input, not the first.
▸Treating pH as the whole compatibility story. Two formulations at the same pH can behave completely differently, because surfactant type, solvent content and essential-oil load are separate variables.
▸Assuming a hot fill is a resin swap. Above the material’s window it is a tooling and geometry change, including vacuum compensation panels.
▸Specifying recycled content as a decoration. PCR brings a colour cast and a documentation obligation. Both belong in the specification, not in the marketing brief.
▸Sourcing the closure separately from the bottle. The neck is the most highly stressed area of the pack. Neck and closure are one assembly, and they should be specified as one.
▸Leaving the fill temperature until the sample arrives. It is an input to the specification, so a late change costs a tool rather than a drawing.

Each of those is cheaper to settle as a question than as a rework.

Material selection: buyer questions

Which plastic is best for cosmetic packaging?+

It depends on the fill and on whether the pack has to be seen. PET is the usual starting point for clear, cold-filled cosmetics because it combines clarity, rigidity and the lowest cost per unit of the clear materials. HDPE, PE and PP are the usual starting points where the fill is aggressive or the pack does not need to be clear. There is no material that is best across the board.

Is PET or HDPE better for a shampoo bottle?+

Suitable candidates are HDPE and PE where the fill is surfactant-heavy and the pack is opaque; PET where a clear or tinted body is part of the brand. Consider HDPE when chemical resistance and stress-crack resistance lead; consider PET when the fill is meant to be visible and the formula is mild. Depends on the surfactant system and the fill temperature.

What is the difference between PET and PETG?+

PET is a semi-crystalline polyester, so thick walls haze. PETG is glycol-modified and stays clear at 3–5 mm, which is why it is used for heavy-base serum bottles and thick-wall jars. PETG costs more, has a lower heat ceiling, and is more sensitive to solvents and essential oils than PET.

Can I use PCR in a clear bottle?+

Post-consumer recycled PET carries a grey or green cast and higher haze, so it suits opaque or heavily tinted bottles far better than crystal-clear ones. PCR HDPE costs nothing optically, because an HDPE pack was already opaque. Depends on whether your market will accept the colour shift at the content level you want.

How do I know which material will survive my formula?+

Narrow the field with the tables above, then test the actual formula. Compatibility depends on concentration, contact time, storage temperature and mechanical load, not just on the polymer name. We run soak and stress tests on request, and any fill-contact conclusion belongs in a test report naming your formula.

Does a higher recycled content change the material properties?+

Yes. Recycled content shifts colour, raises haze and can introduce a slight odour risk in PET, and it changes the melt behaviour enough that the process window is set again per lot. It does not raise the heat ceiling of the base polymer.

What is the minimum order quantity?+

5,000 pcs per SKU on stock tooling. A custom shape is quoted together with its tooling, because the tool is amortised over the first run.

How long does sampling take?+

From existing tooling, typically 3–10 days. A new private mold is a longer programme and is quoted with the tooling charge.

Send the formula and the format and we will name the candidates

Tell us the fill chemistry, fill temperature, capacity, neck finish and whether the pack has to be clear. We will come back with the materials worth evaluating — not a single verdict.

Talk to Engineering Request a Quote

Part of Plastic Packaging Materials: PET, HDPE, PE, PETG, PP and PCR | Shijin

Keep reading

Material, engineering and buying pages that this one sits next to.

Packaging Engineering: Bottles, Closures and Decoration | Shijin Custom Bottles, Jars & Dispensers — Wholesale Buyer Guides: Sourcing, Specifying and Ordering Packaging | Shijin

Products behind this page

Real items from the Shijin stock-mold library. Shown specifications are the published ones; a quotation is built from your own drawing and fill volume.

PET | 80 ml | SJT0466-80