PP Resin Supplier China | Homopolymer, Random & Impact Grades

How to compare PP grade families

Polypropylene is specified in two steps: grade family first, then melt flow rate (MFR, ISO 1133 at 230 °C / 2.16 kg). Lock the family down before you negotiate price.

Grade family	What it gives you	Where it is used	Confirm before ordering
Homopolymer	Highest stiffness and heat deflection of the PP families	Housewares, closures, crates, extruded sheet, strapping, fibre	MFR window, nucleation, UV package for outdoor service
Random copolymer	Lower haze, better stress-crack resistance, softer feel	Transparent containers, hot-fill packaging, medical disposables	Haze level, extractables, food-contact declaration for the exact code
Impact (block) copolymer	Ethylene rubber phase for impact strength at low temperature	Crates, pails, battery cases, automotive trim and bumpers	Impact value at your lowest service temperature, rubber content
Filled and reinforced	Talc or glass fibre raises stiffness and HDT and reduces mould shrinkage	Under-hood parts, appliance housings, structural brackets	Filler loading, coupling agent, shrinkage difference across and along flow

Specifications to put in your RFQ

Grade family plus MFR window — quote a range, not a single point, so the supplier can offer ex-stock material
Conversion route — injection, blow moulding, extrusion, cast or BOPP film, fibre, or thermoforming
Additive package — UV stabiliser, antistatic, nucleating or clarifying agent, slip and antiblock, flame retardant
Colour route — natural, a named masterbatch reference with let-down ratio, or a pre-compounded colour (RAL or Pantone)
Regulated end use — food contact, drinking water, or medical, with the destination market named
Pack and logistics — 25 kg bags, 1 000 kg big-bags or bulk tanker; palletised, stretch-wrapped, container load versus LCL
Annual volume and call-off pattern — this decides whether a producer quotes a contract programme or a spot price

Documents to request before you pay

Certificate of Analysis for the actual lot: MFR, density, tensile and impact, tied to a batch number you can trace
Technical Data Sheet for the exact grade code, not the family brochure
Food-contact declaration against EU 10/2011 or FDA 21 CFR 177.1520 where the part touches food
REACH SVHC statement and RoHS declaration for electrical applications or European distribution
UL 94 listing if a flame-retardant grade is specified
Safety Data Sheet in the language of the receiving country

Common sourcing mistakes

Enquiring for generic "PP" without naming the family — homopolymer and impact copolymer are not interchangeable in a cold-chain crate
Chasing the lowest MFR-number price while the existing tool was cut for a different shrinkage
Skipping the lot COA and discovering a regrind or off-grade blend only after the tool is running
Neglecting storage: PP absorbs little moisture, but filled grades and masterbatch blends show splay if cold pallets are opened in a humid plant

Frequently Asked Questions

What is the difference between PP homopolymer and PP copolymer?

Homopolymer is propylene alone: stiffer, higher heat deflection, weaker at low temperature. Copolymer introduces ethylene — random copolymer improves clarity and stress-crack resistance, block copolymer adds an impact phase. Your conversion route and service temperature make the choice.

Which MFR should I specify?

Ask your moulder, not the resin seller. High MFR fills thin walls but gives up impact strength; low MFR suits extrusion, sheet and thick sections. Give a window so the supplier can quote stock, not a special run.

Can I buy food-grade or medical-grade PP from China?

Yes, but the grade code matters more than the claim. Request the food-contact declaration against EU 10/2011 or FDA 21 CFR 177.1520 for that specific code, and for medical devices an ISO 10993 assessment on the finished part.

Is recycled PP available?

Post-industrial and post-consumer PCR PP are both traded; colour consistency and odour are the usual constraints. See the recycled plastics category; require the PCR percentage in writing.

How is PP resin priced?

PP follows propylene feedstock and regional capacity, so fixed annual prices are rare. Agree a validity window or an index-linked formula on the quote.