From Batch to Container: 8 Quality Checks We Run Before Your Elastomer Shipment

Time of issue:2026-09-09 18:25

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From Batch to Container: 8 Quality Checks We Run Before Your Elastomer Shipment

What a manufacturer's pre-shipment QC actually covers - and what every COA should show

Most buyers only ever see the last step of quality control: a document in the shipping pocket. As the manufacturing exporter behind TS DOWREN elastomers - TPE/TPR, TPV, TPU and TPEE - we run eight checks on every batch before the container doors close. Knowing them helps you audit any supplier, including us.

In-process and release testing (checks 1-4)

Raw materials are verified against the master formula on receipt. Every production batch is then measured for melt flow index, Shore hardness and specific gravity against its specification window - the three fastest predictors of processability and compound identity, and the first three lines on every COA we issue.

Appearance, contamination and batch consistency (checks 5-6)

Pellets are inspected for black specks, gels and contamination under standard lighting, with colour verified against a retained master chip. We hold retention samples from every lot so your current shipment and your reorder can be compared objectively, batch after batch.

Figure 1. Pellet batch sampling and moisture control before export packing.

Moisture, packaging and documentation (checks 7-8)

Moisture is checked and controlled because damp elastomer pellets process into voids and streaks; foil-lined bags, desiccant and stretch-wrapped pallets protect the load through sea transit. Finally, the COA carries actual measured values - not ranges - plus RoHS and REACH declarations and full batch traceability.

Table 1. The eight pre-shipment checks

	Check	What passes	Why it matters to you
1	Raw material identity	Verified against master formula	Compound stays consistent
2	Melt flow index	Inside spec window	Predictable processing
3	Shore hardness	Inside spec window	Correct feel and sealing force
4	Specific gravity	Inside spec window	Filler level and dosage cost
5	Appearance	No specks, gels or contamination	Clean surfaces, low scrap
6	Colour vs master chip	Match to retained standard	Consistent assemblies
7	Moisture and packaging	Dry pellets, foil-lined bags	No voids or streaks in moulding
8	COA and compliance	Actual values, RoHS/REACH, traceability	Audit-ready documentation

Work with the manufacturer

TS DOWREN manufactures and exports TPV, TPE, TPU and TPEE plus engineering plastics including PEEK, PSU/PPSU, PPS, LCP, PPA and PMMA to customers in over 40 countries. Share your application and target specification: we will recommend a grade, provide datasheet, COA and compliance documents, and arrange samples for moulding or extrusion trials. Reach us at www.dowren.com.

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