TL;DR: When sourcing silicone and RTV sealants from China for regulated markets, the document that most often blocks customs clearance is not the COA — it is the missing or incorrectly scoped SDS, specifically the absence of constituent CAS numbers required under EU REACH Article 31.
TL;DR: In our documentation review program, roughly 60% of first-submission compliance packages from Chinese silicone sealant suppliers fail EU or FDA pre-qualification screening, with SDS deficiencies and missing food-contact migration test reports accounting for the majority of rejections.
Regulatory Frameworks That Actually Govern Market Entry #
Three regulatory regimes matter for silicone and RTV sealants sold internationally: EU REACH/CLP, US FDA (for food-contact and medical applications), and China’s own GB/T system. The compliance requirements under each differ enough that a product correctly documented for one market can be non-compliant in another without any change to the formulation.
Under ECHA REACH, silicone sealants containing substances of very high concern (SVHCs) above 0.1% w/w in the article require notification to the ECHA SVHC candidate list. Cyclic siloxanes — D4 (octamethylcyclotetrasiloxane) and D5 (decamethylcyclopentasiloxane) — are both on the SVHC list and are present as residuals in many one-part RTV formulations. Chinese suppliers frequently report D4/D5 content at “below detection threshold” without specifying the detection method or limit. That answer is not sufficient for EU import compliance.
The EU RoHS Directive applies where silicone sealants are used in electrical and electronic equipment assembly. RoHS compliance for sealants is often overlooked because the directive is primarily associated with component materials — but any sealant incorporated into an EEE product is within scope if it remains in the final article.
For food-contact applications, FDA Guidelines 21 CFR 177.2600 governs rubber articles intended for repeated food contact. Silicone sealants used in food processing equipment, potable water systems, or beverage lines must meet extractables and migration limits under this regulation. The test burden is significant: total extractable matter must not exceed 175 mg per square inch of contact surface, and specific migration of volatile matter must be demonstrated.
| Regulatory Framework | Scope for Silicone Sealants | Key Compliance Trigger | Chinese Supplier Gap |
|---|---|---|---|
| EU REACH (SVHC) | All formulations containing D4/D5 above 0.1% w/w | SVHC notification + SDS Article 31 CAS disclosure | CAS numbers missing or incomplete in SDS |
| EU RoHS | Sealants in EEE assembly | Declaration of conformity + restricted substance testing | RoHS DoC rarely provided proactively |
| FDA 21 CFR 177.2600 | Food-contact and potable water applications | Migration test report, extractables < 175 mg/in² | Migration data almost never available from Chinese suppliers |
| SAC GB/T Standards GB/T 14683 | Domestic China market | Conformity to Chinese building sealant standard | Passes GB/T, may not meet ISO 11600 class requirements |
| ISO Standards ISO 11600 | Construction sealants, EU/international | Movement accommodation class (F or G), adhesion testing | ISO 11600 classification rarely tested by tier-2/3 factories |
| ASTM International ASTM C920 | US construction market | Type S or M, Grade NS/P/T, Class 12.5 to 100 | ASTM C920 classification often self-declared without test data |
The table above summarizes where Chinese supplier documentation most commonly falls short. The GB/T gap deserves specific comment: GB/T 14683 is the domestic Chinese standard for silicone building sealants, and a product that passes GB/T 14683 is not automatically compliant with ISO 11600 or ASTM C920. The movement accommodation class requirements differ, and GB/T 14683 permits wider tolerances on adhesion-in-peel than ISO 11600 Class F. Buyers who accept a GB/T test report as evidence of ISO compliance are carrying undisclosed specification risk.
Where Compliance Packages Break Down — and Why #
The most common failure mode is not fraudulent documentation. It is incomplete documentation that was accurate for the domestic Chinese market but was never designed to satisfy an import regulatory review.
Chinese silicone sealant manufacturers — even reputable tier-1 producers — typically generate compliance documentation against the domestic standard. The SDS is written to SAC GB/T Standards GB/T 16483, not to the EU’s ECHA REACH SDS format under Regulation (EC) No 1907/2006 Annex II. The practical consequence: Section 3 of the SDS (Composition/Information on Ingredients) frequently lists ingredient categories rather than individual CAS numbers. For a simple acetoxy-cure RTV, this means acetic acid off-gassing chemistry, silicone polymer backbone, and filler systems may all be grouped under generic descriptions. EU customs authorities and importers’ compliance teams cannot perform SVHC screening from a category description — they need CAS numbers.
We flag this under our internal CL-09 compliance document review procedure, and it delays qualification timelines by an average of three to six weeks while suppliers update SDS documentation with their raw material formulators.
A second failure mode occurs specifically with food-contact and medical-grade silicone sealants. A supplier may correctly identify their product as “food-grade” based on the base polymer specification — but food-grade polymer is not the same as a food-contact compliant cured article. The crosslinker, plasticizer, and cure catalyst all contribute to the extractables profile. We have seen formulations using platinum-catalyzed addition-cure chemistry — generally the cleanest cure system — still exceed extractable limits because of unreacted low-molecular-weight siloxane oligomers. The test that catches this, ISO 10993-12 for extraction conditions or FDA 21 CFR 177.2600 oven-aging extraction, is rarely conducted by Chinese suppliers without buyer insistence. Without that test report in the file, the “food-grade” claim on the product datasheet is a polymer specification, not a migration compliance declaration.
The third scenario is one that procurement teams encounter specifically when sourcing RTV sealants for electrical enclosure applications: the gap between a UL 508A recognized component listing and a product that merely claims “UL Standards compliance.” UL recognition for a sealant used in industrial control panels requires listing under UL 746C (polymeric materials) with specific flammability ratings — typically 94V-0 or 94HB. We have qualified Chinese suppliers who produced a genuine UL 94V-0 test certificate for their product, valid. The catch: the certificate covered a specific cured thickness (3.2 mm), and the buyer was applying the sealant at 1.0–1.5 mm film thickness. Flammability ratings are thickness-dependent, and a UL test at one thickness does not cover thinner applications. That is the kind of scope mismatch that passes a compliance review on paper and fails a UL listing audit.
Which Standard Should You Specify on the Purchase Order? #
Specify the end-market standard, not the domestic Chinese standard.
This sounds obvious, but procurement teams under cost pressure frequently accept Chinese supplier documentation referencing only GB/T standards because those COAs arrive faster, cost less to produce, and cover the same chemical formulation. The issue is that specification acceptance at the purchase order level establishes the audit trail for your own downstream compliance. If your finished product is sold into the EU and your incoming inspection records reference only GB/T 14683, your compliance documentation chain is broken — regardless of whether the sealant itself would have passed ISO 11600 testing.
For construction and industrial sealants destined for the EU market, specify ISO 11600 classification on the PO and require test reports from an ISO 17025-accredited laboratory. For US construction applications, specify ASTM C920 Type, Grade, and Class explicitly — a Type S (single-component) Grade P (pourable) Class 25 sealant is not interchangeable with a Type S Grade NS Class 12.5, even if both are described as “acetoxy silicone RTV” in the product literature.
The exception: if your supply chain is entirely domestic China with no export obligation, GB/T 14683 is a legitimate and sufficient specification framework. That situation is rarer than it used to be.
Practical Guidance for Buyers #
When sourcing silicone or RTV sealants from China for regulated markets, request the full compliance documentation package before any commercial discussion — not after sample approval. The first document to request is the SDS in the destination-market format (EU REACH Annex II or US GHS-compliant), with CAS numbers listed for all ingredients above 0.1% w/w. This is more diagnostic than the COA: a supplier who cannot produce a properly formatted SDS is almost certainly not equipped to support downstream regulatory audits.
The specific risk to anticipate: a supplier whose SDS lists “siloxane polymer” without a CAS number is signaling that their formulation documentation does not extend to individual constituent level. This matters because SVHC screening under REACH Article 59 requires constituent-level data. If D4 or D5 cyclic siloxane residuals are present above 0.1% w/w, EU notification obligations fall on the importer — and “the supplier didn’t disclose it” is not a regulatory defense.
Before volume commitment, insist on third-party migration testing for any food-contact or potable water application: extraction per FDA 21 CFR 177.2600 with extractable matter below 175 mg/in², or ISO 10993-12 extraction conditions for medical adjacency. Run this on production-representative samples, not lab samples. I’d prioritize getting the migration test on actual production batches — pilot and commercial-scale cure conditions can differ enough to affect extractable levels measurably.
For gaskets and sheet sealing applications that intersect with RTV sealants in assembly processes, the same documentation framework applies.
Frequently Asked Questions #
Does a Chinese silicone sealant supplier need to register under REACH if they are exporting to the EU?
Registration obligations under REACH fall on the EU importer, not the Chinese manufacturer — but the Chinese supplier must provide constituent CAS numbers and substance data sufficient for the EU importer to perform their own SVHC screening and SDS obligations. A Chinese supplier who cannot provide this data creates compliance liability for their EU customer.
Is a “food-grade silicone” product automatically compliant with FDA 21 CFR 177.2600?
No. “Food-grade” typically refers to the base polymer specification, not the cured article’s migration performance. FDA 21 CFR 177.2600 compliance requires extractable matter below 175 mg/in², demonstrated by test. The cure system, crosslinker, and residual oligomers all contribute to the extractable profile and must be included in the test scope.
Can we accept a GB/T 14683 test report as equivalent to ISO 11600 for EU procurement?
No — the movement accommodation class requirements and adhesion-in-peel tolerances differ between the two standards, and a GB/T 14683 report does not constitute ISO 11600 classification. For EU market compliance, require an ISO 17025-accredited ISO 11600 test report.
How often should compliance documentation be revalidated for an approved silicone sealant supplier?
It depends on formulation stability. For suppliers with documented formulation change control procedures, annual review is defensible. For suppliers without formal change control — which covers a larger share of Chinese tier-2 factories than procurement teams generally expect — we run requalification testing every 6 months and request three consecutive batch COAs at each cycle. A raw material substitution at the compounding stage will not appear on a standard COA but will change the SVHC profile and potentially the migration data.
What is the fastest compliance gap to close when a Chinese silicone sealant supplier is otherwise qualified?
Usually the SDS format issue. Updating from a GB/T 16483-formatted SDS to an EU REACH Annex II or US GHS format requires the supplier to work with their raw material formulators to extract CAS-level data — that is the time-consuming part. Once the data exists, reformatting the document is fast. Buyers should budget three to six weeks for this step and not treat it as a formality.
For thread sealants and pipe applications where silicone-based products intersect with fluid system compliance requirements, the REACH and FDA documentation frameworks described here apply with equal force.
Published by sinoraw.com Technical Team | Request a sourcing consultation
