Certification & Documentation Guide for Industrial Coding & Marking Consumables

What Each Document in a Coding Ink Compliance Dossier Actually Contains #

A Certificate of Analysis, a Technical Data Sheet, and a Safety Data Sheet are not interchangeable documents. They answer three different questions. The COA answers: does this specific batch meet the agreed specification? The TDS answers: what is this product designed to do and under what conditions? The SDS answers: what are the handling, storage, and hazard requirements? When QC staff treat these as a package to “collect and file,” critical gaps get missed — typically in the COA, where the tested parameters listed rarely match what the application actually requires.

For CIJ inks, the COA should specify viscosity at 25°C (typically 1.5–4.5 mPa·s for standard grades), conductivity (range varies by printer OEM, typically 800–2500 µS/cm for Videojet and Domino platforms), pigment particle size (D50 ≤ 1.0 µm for food-grade grades to prevent nozzle wear), and solvent composition with percentage by weight for each carrier solvent. If the COA lists only “viscosity: pass” without a measured value and test temperature, it is not a COA — it is a conformance declaration, and the difference matters when you need to trace a production defect back to a batch.

The TDS should include print speed range, substrate compatibility by surface energy (dynes/cm), cure or dry time at stated conditions, and storage temperature range. For thermal transfer ribbons, resin content percentage and back-coat formulation details belong in the TDS, not the COA.

The migration test report is the document that separates a genuinely food-contact-compliant ink from one that merely claims compliance. Under EU Regulation 10/2011 on plastic materials in food contact, overall migration must not exceed 10 mg/dm² and specific migration limits (SMLs) apply to individual regulated substances. A supplier who hands you a COA and a CE declaration without a migration test report from an accredited third-party lab has not demonstrated food contact compliance — they have demonstrated that they have not tested for it.

Where Documentation Breaks Down: Three Failure Patterns We See Repeatedly #

The most common failure is the backdated or template-filled COA. We have received COAs from Chinese suppliers where the batch number on the document did not match the drum label, and where the test date preceded the stated manufacturing date by six days. This happens because some suppliers generate COAs from a master template rather than from actual batch testing. The check is simple: request the raw instrument printout (viscometer readout, conductivity meter log) alongside the COA. Suppliers doing real testing can provide this. Suppliers filling templates cannot.

The second failure pattern involves SDS documents that are not GHS-compliant. Under REACH Regulation (EC) No 1907/2006 and EU CLP Regulation (EC) No 1272/2008, SDS documents supplied into the EU must follow the 16-section format with GHS hazard classifications. We regularly receive Chinese-origin SDS files that use the older HMIS or domestic GB/T 16483 format — technically valid for domestic Chinese shipment under SAC China Standards, but not for EU import. The fix requires the supplier to engage a GHS-conversion service, which takes 3–5 business days and costs roughly $150–400 per SKU. Straightforward, but suppliers consistently fail to flag this proactively.

This is the failure pattern that causes the most commercial damage. A medical device manufacturer we supported in 2023 had qualified a Chinese CIJ ink supplier through sample approval, reviewed the COA and TDS without issue, then placed a volume order for production of packaging printed with lot codes. EU customs requested the full food contact compliance dossier, including migration test data, at the port of entry. The supplier had no migration test data. The shipment was held for 22 days while emergency testing was arranged at a Eurofins facility in Germany. The test itself took 10 days; the specific migration result came back at 8.3 mg/dm² — within the 10 mg/dm² limit, so the ink was ultimately compliant. But the 22-day delay cost the buyer approximately €18,000 in storage fees, expedited freight and production rescheduling. The migration test that could have prevented this costs around €800–1,200 when commissioned proactively.

The third failure pattern is Chinese-only documentation. Many small and mid-tier Chinese coding ink suppliers produce high-quality technical documents — in Chinese. The English-language COA is sometimes a partial translation that omits parameters present in the Chinese original. When we run dual-language document reviews under our QC-11 documentation verification protocol, we find discrepancies in parameter limits or missing test items in roughly one-third of cases. If you are qualifying a new Chinese supplier, request the Chinese original alongside the English version and have them reviewed in parallel.

Do Chinese GB/T Standards Satisfy EU or US Regulatory Requirements? #

They do not, and the assumption that they do is where most documentation gaps originate.

GB/T standards govern product performance and testing methodology within China’s domestic market. A GB/T-compliant coding ink meets Chinese market requirements — but GB/T does not incorporate EU food contact migration testing protocols, FDA 21 CFR indirect food additive classifications, or REACH SVHC restrictions. The standards address different hazard categories with different methodologies and different numerical limits.

For the US market specifically, coding inks used on food packaging must conform to FDA 21 CFR 175.105 (indirect food additives) or meet the requirements of FDA 21 CFR 170.39 (threshold of regulation). A Chinese supplier’s GB/T 26125 (RoHS) test report demonstrates absence of restricted heavy metals — valuable for electronics applications — but it says nothing about FDA food additive status. These are parallel frameworks that happen to share some restricted substance lists but diverge significantly in scope and test method.

Japan presents a different challenge. The Food Sanitation Law administered by the Ministry of Health, Labour and Welfare (MHLW) governs food contact materials with its own positive list system. Chinese suppliers rarely maintain MHLW-compliant documentation unless they have specifically targeted the Japanese food packaging market. If you are sourcing coding inks for a Japanese customer, treat MHLW documentation as a separate qualification track — it will almost certainly require additional testing.

Practical Guidance for Buyers #

When sourcing coding and marking consumables from China, do not start your documentation review with the COA. Start with the SDS.

The SDS tells you immediately whether the supplier is operating at an export-documentation level. A properly formatted, 16-section GHS SDS indicates that the supplier has invested in compliance infrastructure. An HMIS-format or Chinese-only SDS indicates a supplier oriented toward the domestic market — not necessarily a disqualifier, but a signal to probe further before placing a volume order.

The specific risk to manage is the documentation upgrade trap: a supplier who provides adequate sample-stage documentation but cannot sustain that level for production batches. We flag this in our AVL gate review when a supplier produces a migration test report but cannot identify the accredited lab that conducted it or provide the test certificate number. Any credible migration test report should reference the testing laboratory’s accreditation body (DAkkS, UKAS, A2LA, etc.) and include the specific food simulants used (typically simulant D1 at 60°C/10 days for fatty foods per EU 10/2011 Annex V).

Before volume commitment, insist on three consecutive batch COAs with instrument printouts attached, a GHS-format SDS, and — for any food or pharmaceutical packaging application — a migration test certificate from a named accredited laboratory. For thermal transfer ribbon qualifications, add resin content verification by TGA (thermogravimetric analysis) at a minimum of 200°C ramp rate to confirm the stated resin-to-wax ratio.

Sample size for initial qualification: minimum 3 production lots, not 3 samples from the same lot.

Frequently Asked Questions #

What is the minimum documentation set required to import coding inks into the EU for food packaging applications?

For any direct or indirect food contact application, you need at minimum: a GHS-format SDS, a product-level TDS, a batch COA with measured values (not just pass/fail), a Declaration of Conformity referencing EU Regulation 10/2011, and a migration test report from an accredited third-party laboratory showing overall migration below 10 mg/dm² and individual substance results against applicable SMLs. A COA alone does not constitute food contact compliance.

How do I verify that a migration test report from a Chinese supplier is genuine?

Request the full test certificate including the laboratory’s accreditation number, the specific test conditions (simulant type, temperature, duration), and the sample batch number tested. Cross-reference the accreditation number against the relevant national body’s public registry — DAkkS for Germany, UKAS for the UK, CNAS for China. If the report cannot be traced to a verifiable accreditation number, treat it as unverified.

Can a Chinese COA use GB/T test methods and still satisfy EU QC requirements?

It depends on the parameter. For physical properties like viscosity and conductivity, GB/T test methods often align closely enough with ISO equivalents that the values are directly comparable — provided the test conditions (temperature, shear rate, probe type) are stated. For safety and migration parameters, GB/T methods are not equivalent to EU methods and the data cannot be directly substituted. Request the test method code and conditions for every parameter on the COA, then verify alignment with your required standard.

What should I do if a supplier’s SDS is in Chinese only?

Request an English GHS-format SDS as a contractual requirement before order placement. If the supplier cannot provide one, factor in the cost and lead time for third-party translation and GHS conversion — typically $150–400 per SKU and 3–5 business days. For CIJ ink or other coding consumables used in regulated applications, an English GHS SDS is non-negotiable for European import.

Is REACH compliance the same as food contact compliance for coding inks?

No. REACH compliance (absence of SVHCs above 0.1% w/w) is a chemical safety requirement for substances in articles and mixtures placed on the EU market. Food contact compliance under EU 10/2011 requires migration testing under specific food simulant conditions. A coding ink can be fully REACH-compliant and still fail food contact migration limits. Both frameworks apply independently — you need both.

How often should supplier documentation be revalidated after initial qualification?

Annual revalidation is our baseline for established suppliers with stable formulations. If a supplier notifies you of a raw material change, reformulation, or manufacturing site change — even a minor one — trigger an immediate documentation review and request updated COA and SDS. The risk is that a reformulation that the supplier considers minor can alter migration behavior meaningfully. Our QC-11 protocol flags any supplier-declared change as a mandatory documentation re-review event, regardless of the supplier’s own risk assessment.

What is the most common documentation correction request we make to Chinese coding ink suppliers?

Adding measured values to the COA instead of pass/fail checkmarks. Roughly two-thirds of first-submission COAs from new Chinese suppliers list parameters as “conforms” or “qualified” without the actual measured value and its unit. This format tells you nothing about proximity to the specification limit and makes incoming inspection and trend analysis impossible. The correction request is simple: provide the numeric result, the unit, and the test method for every parameter listed.

Published by sinoraw.com Technical Team | Request a sourcing consultation