Documents Behind a Polyethylene Shipment: COA, COO, Packing List and More

Polyethylene (PE) cargoes do not move across international borders on resin specifications alone. The documentary record behind a polyethylene shipment—COA, COO, packing list, commercial invoice, bill of lading, and regulatory declarations—establishes grade identity, origin status, weight reconciliation, and end-use compliance. For high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and medium-density polyethylene (MDPE) consignments, discrepancies between the certificate of analysis and the packing list, or between the certificate of origin and the commercial invoice, can trigger customs inspection, bank refusal under a letter of credit, and demurrage charges that exceed the retained inventory value.

What Must a Certificate of Analysis Confirm for LLDPE Film Resins?

The COA is a batch-specific quality record identifying the producer, production site, grade designation, lot number, production date, and test methods. For LLDPE film grades, the document must align with the actual grade supplied and with the processing window of the buyer’s blown-film or cast-film line. If the reported melt mass-flow rate under ISO 1133-1:2022 at 190 °C/2.16 kg falls outside the specified target, the shear viscosity in the extruder may shift enough to change film gauge uniformity or bubble stability. A butene LLDPE film grade may be reported at 0.8 g/10 min to 1.2 g/10 min; a metallocene-catalyzed hexene LLDPE may be reported at 0.5 g/10 min to 1.0 g/10 min. The COA must state the exact value and the method designation, because sales ranges are not defensible in a nonconformance investigation.

Density is generally reported under ISO 1183-1:2019 or ASTM D1505-18. Film-grade LLDPE is concentrated around 0.918 g/cm³ to 0.925 g/cm³, while many LDPE film resins fall between 0.921 g/cm³ and 0.925 g/cm³. Tensile properties are reported under ISO 527-2:2012 or ASTM D638-14. For PE film resins, the COA may also report additive loadings—slip, antiblock, and polymer processing aid—because these change the film coefficient of friction and seal performance. If the additive loading is reported only as a target value without a lot-specific measurement, the COA has limited value for troubleshooting optical defects or blocking on a high-speed form-fill-seal line.

Published data for any specific grade should be verified against the producer’s product data sheet, because additive packages and catalyst residues differ between slurry-loop HDPE, autoclave LDPE, and gas-phase LLDPE. The COA cannot substitute for a food-contact compliance declaration, even when the resin producer sells the grade into packaging markets.

Sampling consistency is another source of dispute. The COA may be based on pellet samples drawn from a railcar, silo truck, or hopper car. If the buyer tests the received pellets and obtains a different melt mass-flow rate, the comparison is invalid unless both laboratories use the same sample preparation and conditioning. For PE, test specimens are usually conditioned at 23 °C and 50% relative humidity for at least 40 h before mechanical testing under ISO 291:2008. The COA should state the conditioning period. A missing conditioning statement is a recurring audit finding in nonconformance investigations.

Polyethylene Packing List Verification on Container Loading

For containerized polyethylene shipments, the packing list is the basis for verified gross mass (VGM) declarations under SOLAS VI/2. A 40 ft high cube container filled with 25 kg bags on wooden pallets commonly reaches a payload of 24,000 kg to 25,000 kg before road-weight restrictions. The packing list must record bag count, pallet count, net weight, tare weight, gross weight, container number, and seal number. If the seal number on the packing list does not match the seal number on the bill of lading, customs may treat the consignment as a break in the chain of custody. When PE is shipped as a free-flowing pellet in octabins or flexible intermediate bulk containers (FIBCs), the packing list should also capture the intermediate bulk container lot numbers, the stuffing date, and whether the inner liner is a food-contact grade under FDA 21 CFR 177.1520 or EU Regulation 10/2011.

On production-scale filling lines, FIBC spouts are typically rated to fill at 1,000 kg/h to 1,500 kg/h, and each FIBC is weighed after filling to record a net weight within a tolerance of ±0.5%. The same lot-level weight data should propagate to the packing list without rounding errors; a packing list that rounds metric tons can create a conflict with the commercial invoice when a letter of credit requires exact net weights.

Under CFR or CIF shipments, the shipper of polyethylene is responsible for the bill of lading and the freight cost, but the risk transfers to the buyer at the port of loading. The packing list must therefore distinguish gross weight, net weight, and tare weight in a way that survives customs review in both the export and import jurisdictions. A missing tare weight for pallets and stretch hoods is a common cause of weight reconciliation failure when the destination port uses a weighbridge and the stated gross weight varies by more than 1% from the recorded VGM.

Bulk railcar shipments of HDPE or LDPE present a different document flow. The COA may represent a composite sample drawn from a silo after railcar loading, and the packing list may be replaced by a loading report that records compartment numbers, loading temperature, and unloading instructions. Since polyethylene pellets can soften and agglomerate at elevated temperatures, the loading report should state the maximum pellet temperature at railcar loading and the date of loading. This data allows the receiver to check whether silo residence time or hot conveying has altered pellet geometry before the resin enters a vacuum receiver on an injection molding machine.

When a Certificate of Origin Determines Preferential Tariff Treatment

When a polyethylene consignment enters a destination country under a preferential trade program, the certificate of origin determines whether the importer pays the most-favored-nation tariff or a reduced or zero rate. Polyethylene in primary forms falls under HS 3901; LDPE is generally classified under HS 3901.10, HDPE under HS 3901.20, and ethylene-alpha-olefin copolymers under HS 3901.40. The COO must state the rule of origin criterion exactly as required by the applicable agreement. A tariff-shift origin rule may require that the polymerization step occurs in the exporting country, so a COO based on repackaging or compounding in a third country is insufficient. If the COO lists only the exporter’s name and not the plant address, the issuing bank may reject the document under a letter of credit that requires the producer’s address.

Document inspection under UCP 600 does not require identical wording across documents, but data must not conflict. A bill of lading for polyethylene may state a gross weight of 27,500 kg and the packing list may state 27,480 kg; the issuing bank can raise the discrepancy if the credit terms have no weight tolerance. Bulk polymer shipments commonly require a 5% weight tolerance in the credit terms. The certificate of origin must also be issued by the authority named in the credit and be dated before or on the bill of lading date. A common failure in polymer shipments is a COO dating after the shipment date, which undermines origin verification at the destination.

Alongside the COA, COO, and packing list, the commercial invoice must show the Incoterms 2020 rule and the exact polyethylene grade code. For CIP or CIF shipments, the insurance certificate must cover the polymer cargo at 110% of the invoice value and state claims payable in the destination currency. The safety data sheet for polyethylene pellets is not a dangerous goods document; polyethylene is not classified for transport under GHS or CLP. However, if the resin contains a processing aid such as a fluoroelastomer at or above 0.1% w/w, the SDS must disclose the substance under REACH Annex II.

Food-contact grades require a declaration of compliance separate from the COA. Under FDA 21 CFR 177.1520, olefin polymers may be used in contact with food when the final article meets density, thickness, and extractives limits. Under EU Regulation 10/2011, the overall migration limit for plastic food-contact materials is 10 mg/dm². A declaration of compliance should reference overall migration testing under EN 1186 or specific migration methods under EN 13130. A COA that reports ash content under ISO 3451-1:2019 does not by itself establish food-contact suitability. Regulatory authorities at the destination may reject a consignment if the declaration of compliance lists a grade code that differs from the COA or invoice.

Grade-code mismatches are not rare when a distributor consolidates multiple polyethylene lots. A COA may list the producer’s internal grade code, while the commercial invoice uses the distributor’s trade code. Under UCP 600, such data may be acceptable if the goods description is not altered, but the import declaration may require the foreign manufacturer’s name and the producer’s lot number. If the COA is issued by a trader rather than the actual producer, the document should identify the producing plant and the original lot number; otherwise, the receiving converter cannot trace a quality issue back to the production campaign.