How to verify a black masterbatch supplier
Nine checks you can run yourself in about fifteen minutes, using free public registries and the issuing body’s own database. No sample, no deposit, no sales contact required.
Written by Zoe Lin, export manager at E-LUCK, a black masterbatch compounding plant in Huizhou, Guangdong. We pass all nine ourselves — and we show you the queries behind each claim so you can hold us to it.
How this differs from our twelve-check vetting article.
This page is the verification step itself — which registry to query, which certificate database to trust, and a printable record sheet. If you need the whole procurement process — writing the RFQ, requesting documents, running a trial order, and the red flags that end a conversation — that is vetting a black masterbatch supplier: the twelve-check RFQ process.
Why we publish a supplier’s own verification checklist
A checklist only earns trust if the publisher can survive being run through it. Everything below is a check we pass ourselves, using the same public registries we point you to. Our registered name, credit code, four certificate numbers and report numbers are on the certifications page, and the queries behind them are the ones in the third column.
This is deliberately not a “ten questions to ask the supplier” list that ends with “and buy from us”. It is the same document we would hand to a customer auditing us. If a check on this page fails for us, we would rather you found it before the first container than after.
Part 1 — Verify the seller is who they say they are
These four checks take about five minutes and use only free public registries. They answer one question: is there a factory behind the email address?
| Check | What you ask for | Where you verify it | What disqualifies |
|---|---|---|---|
| 1. Registered entity | The full registered legal name — not the brand. Also the registered address and the business scope. | gsxt.gov.cn (National Enterprise Credit Information Publicity System). Search the credit code, not the brand name. | A brand name with no matching legal entity; an address that is a virtual office or a mailbox; a scope that reads only “wholesale” or “trade.” |
| 2. Founding date & size | Date of establishment, registered capital, and whether the entity has changed legal representative recently. | Same registry, plus the change-history (变更) tab. A brand that launched last year claiming 30 years of extrusion experience is describing somebody else’s history. | A company registered a few months before it quotes you 60,000 t/yr of capacity. |
| 3. Real production capacity | Number of compounding lines, screw type, annual tonnage, and whether they compound in-house. | Cross-check the answer against a live video call with the compounding hall running — ask them to pan the camera to the line feeding your grade. Numbers a plant knows instantly are numbers a trader has to look up. | Refusal or delay on a live camera call. Capacity described only in “tons per month” with no line count. |
| 4. Consistency across sources | The same legal name on the certificate, the CoA, the packing list and the invoice. | Compare character by character. A suffix difference (“Technology” vs “Technology Co., Ltd”) is not disqualifying — a different city or a different credit code is. | Documents issued by two different legal entities in the same transaction. |
Part 2 — Verify the documents are real and current
A PDF attachment proves only that someone made a PDF. These five checks turn a piece of paper into evidence, using the issuing body's own public database — never the supplier’s copy.
| Check | What you ask for | Where you verify it | What disqualifies |
|---|---|---|---|
| 5. Quality certificate scope | ISO 9001 (or equivalent) certificate number and the scope line, not just the logo page. | cx.cnca.cn — the CNCA public query. Enter the certificate number. | Status “valid” but the scope says “sales and service” rather than production. That is a trading company certificate. |
| 6. Automotive approval | IATF 16949 certificate number, with the scope and the expiry date. | The IATF public certificate database. If the grade goes into a car part, ISO 9001 alone does not cover the automotive supply chain. | Expired certificate, or one whose scope excludes the product being supplied. |
| 7. Third-party test reports | SGS / Intertek / TÜV reports for RoHS, REACH or PAHs, as your market requires, with the report number. | The laboratory’s own verification page, using the report number. Check the sample date — a two-year-old report describes a formulation that may no longer be the one you receive. | A report number that returns nothing. Test reports the supplier issued themselves carry no weight. |
| 8. Batch certificate of analysis | A CoA for a specific lot, showing the actual measured values — not a generic specification sheet. | Compare the lot number on the CoA with the lot number printed on the bags you receive, and check the shipment date against the CoA date. | A “CoA” that lists only specification ranges. Ranges are what the supplier promises; only measured values tell you what you got. |
| 9. Transport safety document | An SDS (safety data sheet) for the specific grade, and the correct shipping description for your destination. | Check the transport class against your cargo insurer and your freight forwarder’s requirement before booking, not after. | SDS missing entirely, or generic — one SDS for the whole product range. |
Black masterbatch pellets are generally shipped as a non-hazardous, non-regulated solid. The classification is not the number on the supplier’s invoice; ask for the SDS and let your forwarder confirm. See is black masterbatch a dangerous goods? for the detail.
Part 3 — Verify the material performs, not just the paperwork
Every check above is administrative. This one is the only part that tells you whether the material works on your line — and it is the part most suppliers avoid.
Ask for these numbers before you pay for a full order
- Lot-to-lot consistency. Three CoAs from three different production dates of the same grade. Plot the values. Tight variation is the single best predictor of how the grade behaves in month nine, and it is the best free quality signal available to a buyer.
- Dispersion, in a stated unit and a stated method. Filter pressure value, with the mesh and the test method named. Two plants will return different numbers for the same grade because the methods differ — a number without a method is not comparable. We wrote a 15-page paper on exactly this: Measuring dispersion in black masterbatch.
- Screen pack specification. The mesh the compound is stated to pass. This is what protects your extruder from a foreign body, and it is a hard number you can hold them to.
- Let-down recommendation in their words, plus the cost per finished tonne at that ratio — not the price per kilogram of masterbatch. A 13% grade at 5% let-down and a 47% grade at 1.4% can deliver the same blackness at very different delivered costs.
- A trial lot of your own conditions. 1–5 kg is normally free. Run your part on your own tooling before committing a container.
Our own answers, so you can run the checks on us
| Check | Our answer | You can verify it here |
|---|---|---|
| Registered entity | E-LUCK (Guangdong Yijuyuan Plastic Industry Technology Co., Ltd.), Huangxi Industrial Zone, Shiwan Town, Boluo County, Huizhou, Guangdong | Credit code 91441322MA4ULT1D8T on gsxt.gov.cn; established 2016-01-27 |
| Production capacity | 60,000 t/yr, compounded in-house on twin-screw lines | Factory tour video — ask us for a live call and pan to the line |
| Quality certificates | ISO 9001, IATF 16949, ISO 14001, ISO 45001 — four certificate numbers with expiry dates | Numbers and validity dates on /certifications; run each through cx.cnca.cn |
| Third-party reports | SGS: RoHS 9 reports, REACH 8, PAHs 5 | Report numbers on /certifications, verifiable on SGS’s own portal |
| Batch CoA | Issued per lot; lot number printed on the bags | Compare the two numbers when the shipment arrives |
| Dispersion method | Filter pressure value, with mesh and method stated on every report | Free 15-page white paper on why numbers differ and what to compare instead |
| Trial lot | 1–5 kg free sample, shipped on request | Ask for a sample and run your own part |
If any answer above is wrong, or a certificate does not verify, tell us and we will correct this page. Contact: [email protected].
Questions buyers ask about supplier verification
The eight questions that come up most often when a buyer runs these checks for the first time.
Is a certificate PDF enough to prove a supplier is real?
No. A PDF proves only that someone produced a PDF. The certificate number is the document. Enter it in the issuing body's own database — CNCA for ISO certificates, the IATF database for automotive, the laboratory's portal for test reports — and read the status, the expiry date and the scope line. A valid certificate with a scope that says “trading” rather than production tells you the company on the certificate does not manufacture.
What is the fastest single check that separates a factory from a trading company?
Ask how the dispersion of the grade is measured, or what mesh filtration it passes. It takes a factory seconds, because it ran the test on the material it compounded. A reseller has to forward the question and wait. Second fastest is the registered business scope on the national company registry — manufacturing scope and wholesale scope read differently and take ten seconds to compare.
Why do two black masterbatch suppliers quote different dispersion numbers for the same grade?
Because filter pressure value is method-dependent. Different mesh, different filter medium, different test speed and different sample preparation produce different numbers on identical material. A number quoted without its method and unit is not comparable to anything. This is the single most common source of false disputes in black masterbatch sourcing, and it is covered in detail in our free white paper on dispersion measurement.
How many certificates does a black masterbatch factory actually need?
One quality system certificate whose scope covers production is the baseline. Automotive applications add IATF 16949. Export markets add RoHS or REACH reports from an accredited third-party laboratory. ISO 14001 and 45001 are useful but not usually gating. What matters more than the count is whether the scope line covers manufacturing and whether anyone will give you the certificate number so you can verify it.
Should I pay for a video factory audit before the first order?
A live video call costs nothing and separates most traders from plants — ask them to pan to the compounding hall with the line running. A paid third-party audit is worth it for repeat orders or high volume, not usually for a trial tonnage. The eight checks on this page cost nothing and, run together, catch the large majority of problems. They do not replace an audit; they tell you whether an audit is needed.
Is black masterbatch a dangerous good to ship?
Generally no — carbon black masterbatch pellets are normally shipped as a non-regulated solid, which is why they do not carry a UN number. Classification does vary by additive package and destination, so the correct source is the SDS for the specific grade rather than a general statement. Your forwarder and your cargo insurer should confirm before booking. We have written a longer explanation of the regulatory position separately.
What should be in a batch certificate of analysis for black masterbatch?
At minimum: the lot number that matches the bags, the date, and the measured values — not specification ranges. Useful additions are pigment content or carbon black content, sieve residue, dispersion or filter pressure value with its method stated, moisture, and the melt mass flow rate. Ranges tell you what the supplier promises; only measured values tell you what is in your silo.
What is the single most useful thing to negotiate before placing an order?
A written let-down ratio recommendation with the cost per finished tonne at that ratio, and a commitment to a dispersion method and unit. It changes what you are comparing: price per kilogram of masterbatch rewards a high-loading grade that makes you pay freight on carrier resin, while cost per finished tonne rewards the loading that actually delivers your target blackness. See our guide to the let-down ratio calculation.
Take the checklist with you
The same nine checks as a one-page printable sheet, plus our certificate numbers to check us against.
Download the checklist (PDF) See our certificates Send us your grade for a quote
Revision 1.0 · October 2026 · written by the E-LUCK export desk, Huizhou. Registries and databases referenced: National Enterprise Credit Information Publicity System (gsxt.gov.cn), CNCA certificate query (cx.cnca.cn), the IATF public certificate database, and SGS’s own report verification.