How to verify RoHS compliance for industrial adhesives

Are your industrial adhesives RoHS compliant, and can you prove it to an auditor? For quality control and safety managers, a supplier’s assurance is a useful starting point, but it is not a complete verification strategy. The evidence must connect the adhesive actually purchased and used to the restricted-substance requirements that apply to the finished electrical or electronic equipment.

That distinction matters when an adhesive is buried inside a power supply, electronic enclosure or shielding assembly. Once the equipment has been built, identifying the formulation or taking a representative sample may be difficult. A sound review before production can prevent a small material decision from becoming a larger compliance problem.

Does RoHS apply to the adhesive or to the finished equipment?

The EU Restriction of Hazardous Substances Directive, commonly called RoHS, restricts specified substances in electrical and electronic equipment (EEE) placed on the EU market. The principal legislation is Directive 2011/65/EU, as amended. The ten-substance list includes four phthalates added through Directive (EU) 2015/863.

An industrial adhesive sold as a material is not automatically subject to the same obligations as a finished piece of EEE. Nevertheless, when that adhesive remains in equipment within RoHS scope, its composition can affect the compliance of the finished product. Equipment manufacturers therefore commonly ask adhesive suppliers for declarations and supporting evidence.

Begin by documenting the intended use. Is the adhesive bonding a sensor inside an electrical cabinet, securing a component in a consumer device, or sealing an industrial structure with no relevant electrical function? The answer influences whether EU RoHS is applicable and what evidence is proportionate. Equipment scope, exclusions and exemptions can be complex, so do not assume that every product used in an industrial or aerospace setting is automatically excluded.

Also distinguish RoHS from other market requirements. EU RoHS is not the same as REACH, and a statement addressing one does not establish compliance with the other. Other jurisdictions may have their own RoHS-like rules, so identify the destination market and applicable legislation before accepting a generic declaration.

Know the restricted substances and concentration limits

For EU RoHS, the maximum concentration values are generally expressed by weight in each homogeneous material, not as an average across the complete product. A homogeneous material is one of uniform composition throughout, or one that cannot be mechanically separated into different materials by actions such as cutting, grinding or abrasive processes.

For an adhesive bond, the relevant material is generally the adhesive as it remains in the finished equipment. Depending on the formulation and whether constituents are mechanically separable, an assessment may need to consider distinct materials rather than treating an entire assembly as one sample. The metal housing, surface coating, adhesive and attached component cannot simply be averaged together to dilute a restricted substance.

Concentration limits do not mean that a substance must be intentionally added to cause a problem. Impurities, pigments, fillers, recycled inputs or contamination during manufacture can also be relevant. Conversely, the presence of a restricted substance below the applicable limit is not, by itself, a RoHS failure.

What evidence should you request from an adhesive supplier?

A useful supplier package should let a reviewer identify the material, understand the claim and trace the claim back to supporting information. Ask for documentation tied to the exact trade name, product code and, where relevant, formulation or revision being purchased.

• A RoHS material declaration: It should identify the applicable legislation, address all ten restricted substances, state whether the material meets the concentration limits and disclose any exemption relied upon.
• Composition or substance information: Request sufficient information to assess the material and potential risks. A full material disclosure may be preferable where available, although confidential formulations can require a more limited declaration and supporting assessment.
• Supporting test reports or other evidence: These may include laboratory results, raw-material declarations and a documented risk assessment. Check that the evidence covers the substances and materials relevant to the claim.
• Change-control commitments: Ask how the supplier will notify you about formulation, raw-material source, manufacturing location or product-code changes that could affect the declaration.

A safety data sheet is useful for handling and hazard communication, but it is not a substitute for a RoHS declaration. Its disclosure thresholds and purpose differ from RoHS requirements, so the absence of a substance from an SDS does not prove that the adhesive meets a RoHS concentration limit.

Similarly, a certificate stating only “RoHS compliant” leaves important questions unanswered. Which product does it cover? Does it address the current ten substances? Is it based on the supplied formulation, and is an exemption involved? If the answers are missing, ask for clarification before the material is approved.

Review the declaration, not just its signature

Check the declaration date against the purchasing and production timeline. A recent signature is helpful, but age alone does not determine validity: a well-supported declaration can remain relevant if the formulation and applicable requirements have not changed. Equally, a newly issued document may be weak if the supplier cannot explain its basis.

Pay particular attention to two-part adhesives. Identify both resin and hardener, the specified mix ratio and the expected cured bond. Supplier evidence should explain what was assessed and how that assessment relates to the material left in the equipment. Do not assume that a declaration for one component covers the complete system.

When should industrial adhesives be tested for RoHS compliance?

Testing is most useful when it addresses a specific uncertainty. For a stable formulation from a supplier with strong declarations and change controls, a documented assessment of existing evidence may be appropriate. Additional testing deserves consideration when the supplier cannot substantiate a claim, the formulation changes, the material has a higher-risk ingredient profile or a customer contract requires test data.

IEC 63000 provides a framework for preparing technical documentation for assessing electrical and electronic products with respect to the restriction of hazardous substances. The IEC 62321 series describes test methods for determining certain regulated substances in electrotechnical products and materials. These standards support a structured assessment, but following a test method does not automatically make every sample representative of every adhesive batch.

Before commissioning a laboratory, agree on the following:

• Sample identity: Record the product code, lot number, receipt date and supplier. Retain a reference sample where practical.
• Material condition: Specify whether the sample is uncured, mixed or cured. For a finished-equipment assessment, discuss how the prepared specimen represents the adhesive as used, including mix ratio and cure conditions.
• Substances and methods: Confirm which of the ten substances are covered, the analytical methods and the laboratory’s relevant competence or accreditation scope.
• Reporting limits: Verify that detection or quantification limits are low enough to support a decision against the applicable RoHS thresholds, particularly for cadmium.
• Decision rules: Agree how measurement uncertainty, screening results and any necessary confirmatory analysis will be handled.

X-ray fluorescence, or XRF, can be useful as a screening tool for certain elements, but it has limitations. A total chromium result, for example, does not establish how much hexavalent chromium is present. Elemental bromine screening does not identify individual PBB or PBDE compounds, and XRF does not directly determine the four restricted phthalates. A screening result may therefore need substance-specific follow-up before a compliance decision can be made.

A report showing results below reporting limits is meaningful only when those limits are appropriate and the sample represents the material in question. It should not be treated as proof that all future lots will remain unchanged.

Exemptions require a separate decision

Some restricted-substance uses may be covered by exemptions in the RoHS directive. An exemption is not a general permission to exceed a limit whenever a material is difficult to replace. It applies only to the specified use, subject to its wording, equipment categories and applicable dates.

If a supplier declaration cites an exemption, obtain the exact exemption number and description. Then determine whether it genuinely covers the substance, material and application in your equipment. Record the relevant expiration date and monitor regulatory updates. A supplier’s reliance on an exemption does not remove the equipment manufacturer’s responsibility to assess whether that exemption applies to the finished product.

For adhesives used in demanding electrical assemblies, there may be pressure to retain a familiar formulation because it meets mechanical, thermal or sealing requirements. Treat any exemption review as a joint technical and compliance decision: replacing a material without qualifying its bond performance can create a different risk, while assuming an exemption applies can leave a regulatory gap.

Build a traceable record that can survive an audit

The strongest compliance file follows the adhesive from approval through production. An auditor should be able to move from a finished equipment configuration to the adhesive specification, supplier declaration and supporting assessment without relying on someone’s memory.

1. Define the scope. Record the equipment model, destination market, applicable RoHS requirements and the adhesive’s function in the assembly.
2. Identify the material. Link the approved product code, supplier, formulation or revision and purchasing specification to the bill of materials or manufacturing instructions.
3. Assess the evidence. Review declarations, raw-material information and relevant test reports against all ten substances. Document gaps and the rationale for accepting or requesting further evidence.
4. Resolve exemptions and deviations. Record any exemption assessment, open questions, corrective actions and approval authority.
5. Control changes. Connect incoming lots to production records where feasible, and require reassessment when a supplier, formulation, process or regulatory requirement changes.

Keep the assessment with the finished-product technical documentation, alongside other relevant conformity evidence. For in-scope EEE, the manufacturer is responsible for the product’s EU conformity assessment, EU declaration of conformity and CE marking obligations. An adhesive supplier’s declaration supports that process; it does not replace the manufacturer’s assessment of the complete equipment. A standalone adhesive declaration should not be confused with CE certification of the adhesive for RoHS purposes.

Common review findings that are easy to miss

A report covers the wrong product. Similar names can conceal different fillers, colours, cure systems or regional formulations. Match the precise product code and revision, not just the supplier’s brand.

The evidence covers only part of the substance list. Older documents may address six substances but omit the four restricted phthalates. Check the actual scope rather than relying on the document title.

A pass result is applied too broadly. One tested lot can inform a risk assessment, but it does not establish ongoing control across every production site and formulation. Supplier change notification and periodic review remain important.

Packaging is confused with the bond material. A cartridge, mixing nozzle or label may matter under other requirements, but it should not be mistaken for the adhesive that remains in the equipment. Define the assessment boundary clearly; if a packaging component becomes part of the finished product, assess it accordingly.

For teams comparing materials across sealing, bonding and shielding applications, the practical question is not merely whether an adhesive is described as RoHS compliant. It is whether the available evidence supports that conclusion for the specific material, configuration and market. G-SCE’s technical benchmarking perspective reinforces that connection between material selection, documented standards and the integrity of the finished assembly.