HDPE Resin Supplier China | ESCR, PE100 & Blow Molding

Start from the failure, not the datasheet

Enquiries usually open with density and melt index, because that is what a datasheet leads with — yet neither predicts how a container, pipe or crate fails in service. Name the failure first:

Slow cracking — bottles holding surfactants, oils or detergents that split weeks later.
Long-term pressure — pipe holding hydrostatic load for decades.
Cold impact — crates dropped in a cold warehouse.
Melt behaviour — parison sag in blow moulding, short shots in thin-wall injection.

ESCR: the number missing from most enquiries

Environmental stress crack resistance is how long a stressed HDPE part survives in a crack-promoting medium. Ask for ASTM D1693 with the F50 result, reagent and condition, since results are not comparable across conditions. Two grades of identical density and melt index can differ enormously here.

When it must be in the enquiry

Wherever contents or surroundings promote cracking: detergent and cleaner bottles, agrochemical and lubricant containers, tank linings, and parts under permanent assembly stress such as snap-fits or crimped closures.

How to specify it

State the contact medium, service life and test standard, then require the measured value on the lot COA — not a generic “good ESCR” claim.

Pipe and pressure: what the PE100 class says

Pipe compounds are classified by minimum required strength (MRS) under ISO 12162: PE100 denotes an MRS of 10 MPa, PE80 a lower class. That is a material class, not a pressure rating — what a finished pipe carries also depends on wall series, design factor and the product standard it is certified against. Request the compound class with its MRS evidence and the pipe's rated pressure separately. The comparison is written out in PE100 vs PE80.

Melt index points in opposite directions

Melt index is not a quality grade, it is a direction. Low MI holds melt strength, which blow moulding and pipe extrusion need against sagging. High MI fills thin walls fast, which injection moulding of crates, bins and closures runs on. Copying one melt index from a film line to a blow moulder is the usual reason a good resin runs badly.

Application → the number to ask for

Application route	Fails first by	Ask the TDS for	Then confirm
Blow-moulded containers	Cracking in service	ESCR, F50 + condition	Chemical compatibility
Pressure pipe	Slow crack growth	MRS class + rating	Pipe standard certification
Crates, pallets, bins	Cold-drop impact	MI + impact at temp	Tooling at custom molding
Film and sacks	Dart impact, tear	MI, density, slip	Output and gauge
Tanks, rotomoulding	UV embrittlement	MI + UV / carbon black	Outdoor exposure statement

Documents to request before you pay

Lot COA — density, MI, and the ESCR or impact figures your application needs, tied to a batch number
TDS for the exact grade code, not the family brochure
Food-contact declaration — EU 10/2011 or FDA 21 CFR 177.1520
Drinking-water approval recognised in the destination market
REACH SVHC, RoHS and an SDS in the receiving country's language

Where HDPE sourcing goes wrong

Buying on density and MI alone for a detergent container — the failure mode is ESCR.
Reading “PE100” as a pressure rating and sizing a line from it.
Reusing one melt index across blow moulding and injection.
Skipping UV stabilisation outdoors, then blaming the resin.
Assuming recycled HDPE behaves like virgin — require PCR percentage and measured properties in writing from recycled plastics.

Frequently Asked Questions

Is HDPE always better than LDPE?

No — different branches, not better and worse. Density and chain branching decide stiffness and softness; HDPE vs LDPE sets it out.

Can one grade cover blow moulding and injection?

Rarely well. Melt index runs opposite ways for the two processes; give your converter the process and let it set the window.

What does PE100 certify?

A material class by MRS under ISO 12162, not a pipe pressure rating. Ask for both numbers separately — see PE100 vs PE80.

Is HDPE safe for food and drinking water?

Only grade by grade and market by market. Request the declaration for the exact code, plus the approval recognised where the water is delivered.

Is recycled HDPE available?

Yes, mostly into non-food packaging, pipe cladding and crates. Colour, odour and gel count are the usual constraints; require the PCR percentage in writing.