RoHS Compliant Silicone Parts: Testing and Documentation

Silicone rubber does not contain RoHS-restricted substances in its base polymer. Polydimethylsiloxane (PDMS) is built from silicon, oxygen, carbon, and hydrogen only. The compliance risk comes from additives. Pigments can carry lead or cadmium. Some heat stabilizers contain chromium compounds. Crosslinker carriers may bring trace phthalates. Proper testing of the finished compound, not just the base material, is what produces a defensible RoHS declaration.

Dabojin tests silicone compounds to the IEC 62321 series of methods and provides test reports and Certificates of Conformance with orders that require RoHS documentation.

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RoHS 2 restricted substances and limits

RoHS 2 (Directive 2011/65/EU, amended by Delegated Directive (EU) 2015/863) restricts ten substances in electrical and electronic equipment placed on the EU market. Cadmium has the strictest limit at 100 ppm. The remaining nine substances are limited to 1,000 ppm by weight in homogeneous material.

The four phthalates (DEHP, BBP, DBP, DIBP) were added by Delegated Directive (EU) 2015/863 and became enforceable on 22 July 2019 for most equipment categories. Medical devices (Category 8) and monitoring and control instruments (Category 9) had until 22 July 2021 to comply. Some buyers refer to the amendment as "RoHS 3." If your application requires current RoHS 2 compliance, confirm the test report date covers all ten substances, not just the original six.

Test methods: ICP-OES and GC-MS

RoHS compliance testing follows the IEC 62321 series. Two analytical methods cover all ten restricted substances.

Test results: silicone rubber RoHS compliance

The table below shows RoHS compliance test results for a Dabojin silicone rubber compound. All ten restricted substances were not detected (N.D.) at or above the method detection limits, confirming compliance against current RoHS 2 thresholds.

Results are for the specific silicone compound tested. Different pigment systems, crosslinker packages, or material lots require their own test. Full test report and lot-specific Certificate of Conformance available on request.

REACH compliance for silicone

REACH (Regulation EC 1907/2006) is a separate EU regulation that runs alongside RoHS. Where RoHS restricts specific substances in electrical and electronic equipment, REACH governs substances of very high concern (SVHCs) across all article types placed on the EU market.

For silicone specifically, three cyclic siloxanes are on the REACH SVHC candidate list: D4 (octamethylcyclotetrasiloxane), D5 (decamethylcyclopentasiloxane), and D6 (dodecamethylcyclohexasiloxane). All three were added in June 2018 due to persistent, bioaccumulative, and toxic (PBT) or very persistent, very bioaccumulative (vPvB) properties. In the consumer products space, D4 has been prohibited in cosmetics since 2019 (Commission Regulation (EU) 2019/831), and D4 and D5 have been restricted in wash-off cosmetic products at concentrations ≥0.1% w/w since January 2020 (Commission Regulation (EU) 2018/35). A further restriction (Commission Regulation (EU) 2024/1328) extends limits on D4, D5, and D6 to leave-on cosmetic products, with a transition period running to 2026.

For industrial silicone parts, the obligation under REACH Article 33 applies. Suppliers must communicate to business customers when an article contains more than 0.1% w/w of any SVHC, including the substance name and information for safe use. Consumer requests for the same information must be answered within 45 days, free of charge, under Article 33(2).

Dabojin can provide an SVHC declaration covering the silicone compound supplied. Specify this requirement at the enquiry stage and we include it in the documentation package.

Compliance documentation Dabojin provides

Compliance documentation is part of the standard package available for every order. Specify your documentation requirements at the enquiry stage and we confirm what is available for the compound and batch in question.

• Third-party RoHS test report covering all ten restricted substances, tested to IEC 62321 series methods
• Batch-level Certificate of Conformance linking test results to the specific material lot supplied
• SVHC declaration under REACH Article 33 confirming presence or absence of candidate list substances at the 0.1% w/w threshold
• Material Safety Data Sheet covering composition and handling of the silicone compound
• Material traceability record tracking each raw material lot from incoming inspection through to packing list
• PPAP Level 3 package available for automotive programs requiring it

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Frequently Asked Questions

Is silicone RoHS compliant?

Base silicone polymer (PDMS) contains no RoHS-restricted substances. The compliance risk comes from additives. Pigments, heat stabilizers, and crosslinker packages can carry restricted metals or phthalates depending on the formulation. The finished compound must be tested to confirm compliance. Untested silicone cannot be declared RoHS compliant regardless of base material.

Is silicone rubber RoHS compliant by default?

No. RoHS compliance applies to a specific compound formulation, not to silicone rubber as a material class. A compound with cadmium-based red pigment will fail cadmium limits. The same part in unpigmented or carbon-black-pigmented compound may pass all ten substances. Testing the finished formulation is the only way to confirm compliance.

Is silicone sealant RoHS compliant?

Silicone sealants used in electronic assembly must be tested to the same IEC 62321 standard as molded parts. The sealant formulation determines compliance. Crosslinkers, catalysts, and any fillers all affect the result. Acetoxy-cure and neutral-cure sealants have different additive profiles and must be tested separately. A sealant cannot be assumed compliant based on its base silicone content alone.

Does silicone need REACH compliance documentation?

Yes, for EU market supply. REACH Article 33 requires suppliers to inform business customers when an article contains more than 0.1% w/w of any SVHC on the candidate list, including the substance name and information for safe use. Consumer requests must be answered within 45 days. D4, D5, and D6 cyclic siloxanes are on the candidate list. A silicone supplier must be able to provide an SVHC declaration covering the compound supplied.

What documentation do I need from my silicone supplier for RoHS compliance?

At minimum: a third-party test report covering all ten RoHS 2 substances tested to IEC 62321 methods, and a Certificate of Conformance linking the test results to the batch supplied. For EU-placed articles, add an SVHC declaration under REACH Article 33. For regulated industries such as automotive or medical, a full material traceability record linking raw material lots to the finished batch is also standard.

How do I specify RoHS compliance when ordering custom silicone parts from Dabojin?

Note the compliance requirement in your enquiry or on your drawing. Specify which documentation you need: test report, Certificate of Conformance, SVHC declaration, or PPAP-level material documentation. We confirm availability for the compound during DFM review and include the documentation package in the quote. Requirements flagged after production begins may need additional testing time.

See also

• Importance of Biocompatibility Testing
• Comprehensive Guide to GC-MS Testing in Silicone
• Environmental Safety Standards for Silicone
• ICP-OES for Silicone Rubber Test Report (Sample)
• Proposition 65 Safety Tests for Silicone
• Silicone Testing for Medical Devices
• Understanding EN 71-3 Testing Methods for Silicone Rubber