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An impurity in a polymer is defined as an unintended constituent present in the manufactured polymer substance. It may originate from the starting materials, such as the monomers or any other reactants, or be the result of secondary or incomplete reactions during the production process. While it is present in the final substance it was not intentionally added. Examples of impurities in a polymer include unreacted monomers or other reactants, residual polymerisation catalyst, or any contaminant from the manufacturing process. The definition and detailed guidance on how to handle impurities can be found in Section 4.2.- 'Substances of well defined composition', Section 4.3.- 'UVCB substances', and Chapter 5- 'Criteria for checking if substances are the same' of the Guidance for identification and naming of substances Under REACH and CLP: http://echa.europa.eu/guidance-documents/guidance-on-reach
Natural polymers are understood as polymers, which are the result of a polymerisation process that has taken place in nature, independently of the extraction process with which they have been extracted (i.e. they may or may not meet the criteria set out in Article 3(39) of the REACH Regulation).
Following Article 2(9) of the REACH Regulation, any polymer meeting the criteria of Article 3(5) of the REACH Regulation does not have to be registered. This includes natural polymers, which are chemically modified (e.g. post-treatment of natural polymers).
Monomer substance(s) or other substance(s) in the form of monomeric units and chemically bound substance(s) originating from the natural polymer can for practical reasons be treated as "non-isolated intermediates" and do not have to be registered. The substances used to chemically modify the natural polymer and which are chemically bound within the final polymer need to be registered according to the REACH requirements.
This FAQ has been agreed by the Competent Authorities of the Member States (REACH CA) in October 2008.
Yes. The registration of a monomer or other substance chemically bound to a polymer has to include spectral data and a chromatogram of the original monomer or other substance used to manufacture the polymer.
If it is not technically possible, or if it does not appear scientifically necessary to include this information, the reasons need to be clearly stated. Generic spectral data or a generic chromatogram cannot be accepted as this would not reflect the actual composition of the monomer or other substance used to manufacture the polymer.
It may be the case that a company imports a type of polymer from different sources, and therefore a monomer or other substance used in the manufacture of this polymer probably also stems from different sources. Even when a company imports a polymer from just one source, it can happen that a monomer or other substance used in the manufacture of this polymer stems from different sources.
In these cases, the importer of the polymer is responsible for assessing the sameness of the monomer or other substance from the different sources. If they consider that the substances from the different sources are the same, they have to submit just one registration for this substance with one set of spectral data and one representative chromatogram. In this process, they might still have found out that the substance from the different sources has different impurity profiles. They need to then refer to these different compositions of the substance in their registration dossier.
Natural proteins may be considered as polymers under REACH provided that they have at least 50 weight percent of polymer molecules (in this case, molecules including a sequence of at least four amino acid monomer units) and the content of molecules presenting the same molecular weight remains below 50 weight percent.
Similarly, hydrolysed natural proteins may be considered as polymers if they fulfil the abovementioned criteria. If the degree of hydrolysis is to such an extent that less than 50 percent of the weight of the substance consists of polymer molecules (as defined in chapter 2.2 of the Guidance for monomers and polymers) and/or the amount of polymer molecules presenting the same molecular weight is at least 50 weight percent, the hydrolysed natural protein is not a polymer and, hence, is not covered by the registration exemption for polymers under REACH.