Materials Knowledge Base

Plastic Packaging Materials: PET, HDPE, PE, PETG, PP & PCR

Seven materials, one decision: what the fill does to the container, what the shelf has to show, how hot it is filled, and what the brand has committed to on recycled content. These pages carry the numbers behind each resin we run.

Quick answer

Which plastic packaging material you need is decided by four things, not by preference

Shenzhen Shijin molds PET, HDPE, PE, PETG, PP and PCR packaging in-house across two plants in Shenzhen Pingshan and Huizhou Huiyang, plus a Guangzhou office. The material decision comes down to four inputs: what the formula does to the polymer (pH, surfactants, solvents, essential oils, alcohol), 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 after that.

Below is the factual comparison, then a page per material with its properties, applications, manufacturing considerations, limits and evidence.

2,000+

Stock molds

646

PET bottle molds

427

PE bottle molds

15,000㎡

Two-plant floor area

200,000 pcs/day

Blow-molding capacity

23 yrs

Export experience

Compare

Material comparison

No material on this list is the best one. Each is suitable for a defined set of fills, formats and price points — read the last column as the condition that decides it.

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)	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 the pack must survive rough distribution
PE (LDPE / MDPE)	Translucent	High	Squeeze packs, lotion, shampoo	Widely accepted	Consider when the pack has to be squeezed or the formulation attacks PET
PETG	Very high, stays clear in thick walls	Medium — sensitive to some oils and alcohols	Premium serum, thick-wall jars	Depends on system — not accepted everywhere	Consider when the brief needs a heavy glass look PET cannot hold
PP	Low to medium, milky	High	Closures, pumps, jars, hot-fill adjacent packs	Widely accepted	Consider when heat resistance or closure performance leads
PCR PET	Low to medium (grey or green cast)	Medium	Non-clear bottles, 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

Material pages

A page per material

Properties, applications, manufacturing considerations, advantages, limitations, recycling route, direct comparison and the stock molds available in each resin.

PET · 646 molds

PET Plastic Packaging

Transparent polyester. Intrinsic viscosity 0.70–0.85 dl/g for blow-molding grades, good moisture barrier, mainstream recycling stream.

HDPE · 22 molds

HDPE Plastic Packaging

Density 0.941–0.965 g/cm³. Stiff and opaque with very good stress-crack resistance and a fill window PET cannot reach.

PE · 427 molds

PE Plastic Packaging

The polyethylene family graded by density: LDPE squeezes, MDPE balances, HDPE stiffens. Melt flow index is the number that decides how it molds.

PETG · 13 molds

PETG Plastic Packaging

Glycol-modified PET. Holds a 4 mm wall clear where PET hazes, tough on impact, with a lower heat ceiling and higher cost.

PP Plastic Packaging

Semi-translucent, heat-resistant and the polymer behind almost every cap, pump and sprayer we ship.

PCR

PCR PET Packaging

Post-consumer recycled PET, typically 30–100% with 50% the common commercial compromise. Colour cast and haze decide where it can be used.

PCR

PCR HDPE Packaging

Post-consumer recycled HDPE for cleaning and industrial packs, where opacity costs nothing because the pack was never clear.

How we decide

From formula to specification

The sequence below is the order we actually work in. Skipping step one is what produces a bottle that passes sampling and cracks in a warehouse six weeks later.

Fill chemistry first

pH, surfactant type and load, solvent and alcohol content, essential-oil load. Environmental stress cracking and chemical attack are compatibility questions, and they are settled before tooling.

Fill temperature second

Hot fill runs 82–93 °C and needs heat-set resin plus vacuum compensation panels. Warm fill sits around 60–75 °C. Most cosmetics are cold filled.

Appearance and format third

If the fill has to be seen, PET or PETG. If it does not, HDPE, PE, PP and PCR HDPE give more chemical resistance and a far lower cost per unit.

Recycled content last

PCR is a specification decision, not a decoration. Decide the target, then accept the colour cast the content level brings with it.

Evidence

The same controls run on every material

▸Prime virgin resin only for cosmetic and personal-care work — a single heat history, full data sheet and full COA. That is a different material from wide-spec off-grade, post-industrial regrind (PIR), post-consumer recycle (PCR) or in-house rework.
▸Per-lot Certificate of Analysis. Intrinsic viscosity and ash content for PET and PETG; melt flow index (MFI), density and ash content for PE and PP (ISO 3451 / ASTM D5630).
▸Two-way traceability. Resin lot → work order → finished-goods lot, walkable in both directions, so a question about a shipment eighteen months later can be answered.
▸In-process and outgoing inspection. Wall thickness at four points per cavity, weight tolerance ±2%, visual defect inspection every 30 minutes, then AQL 2.5, a 1.2 m drop test, air-pressure leak testing on all closures and a QC report per lot.

Minimum order quantity is 5,000 pcs per SKU on stock tooling, and sampling from existing tooling typically runs 3–10 days. A new shape is quoted with its tooling cost, because the tool has to be amortised over the first run.

On certification wording

Documentation discipline: ISO 9001 is the certification we hold. Supplier audit reports, material COA and migration test reports are issued as documents on request — they are evidence, not certifications.

Only ISO 9001 is described on this site as a certification. Everything else is presented as what it is: a report, a certificate of analysis, or a supply-chain document issued for a specific lot.

FAQ

Common questions about plastic packaging materials

What materials do you mold?+

PET, HDPE, PE (LDPE and MDPE), PETG and PP, plus PCR PET and PCR HDPE where recycled content is specified. PET and PE account for the largest part of the mold library.

Which material should I choose for a clear cosmetic bottle?+

PET is the default for clarity, rigidity and cost. PETG is specified when the design needs a thick wall that would haze in PET, or when impact strength is the real risk. Neither should hold strong acid or alkali fills.

Which material handles aggressive formulations?+

HDPE, and PE generally. They resist the surfactants, solvents and alkalinity that attack PET, and they have very good environmental stress-crack resistance. The trade-off is appearance: they are opaque or translucent.

Can you supply recycled-content material?+

Yes. PCR PET and PCR HDPE are quoted per order with the recycled content level you specify, and the documentation that goes with it. Note that our cosmetic-contact bottles are run on food-grade prime virgin resin as standard.

What is the minimum order quantity?+

5,000 pcs per SKU on stock tooling. Custom shapes are quoted with the tooling charge, since 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.

Are your materials BPA-free?+

The cosmetic-contact materials we run — PET, HDPE, PE, PETG and PP — are inherently BPA-free and phthalate-free. PET and PETG are polyesters; HDPE, PE and PP are polyolefins; none of them use BPA as a monomer.

What documentation can you provide?+

ISO 9001 certification for the quality management system, per-lot resin COA, material data sheets, migration test reports where the application needs them, and supply-chain documentation for recycled content. Ask for the report that matches your application.

Send us the formula and the format, and we will name the material

Tell us the fill chemistry, fill temperature, capacity, neck and whether the pack has to be clear. We will confirm the resin, the mold and the closure together before anything is quoted.

Talk to Engineering Request a Quote

Keep reading

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

PET vs HDPE vs PETG vs PP: Choosing a Packaging Material | Shijin 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.

PETG | 500 ml | SJE1697-500