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- Practical Guide -
Page 36 of 153
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Natural or synthetic macromolecular substances used in the manufacture of modified macromolecules, if the monomers or
the other starting substances required to synthesise them are not included in the list;
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Substances used to modify existing natural or synthetic macromolecular substances."
Consequently, components such as:
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Impurities of starting materials
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Reaction intermediates (e.g. oligomers, products of side reactions)
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Decomposition products
are not included in this list.
The identification of substances to be included in the EU list is not so easy and some
explanation is given below (see 3.1.1 and 3.1.2). However, it should be remembered here
that in the new version of the "Note for Guidance", the SCF requires for monomers "...
information on the migration of oligomers and reaction products from polymers produced
from new monomers or which are produced by means of polymerisation aids that
influence the molecular structure or molecular weight of the polymer. In the first instance
there is a need for information on the identity and level of substances that migrates as a
consequence of the use of a new monomer..."
3.1.1. Monomers and other starting substances in thermoplastics polymers
Thermoplastic polymers: Polymers which are capable of being repeatedly softened by heat
and hardened by cooling. Typical of the thermoplastic family are the styrene polymers and
copolymers, acrylics, cellulosics, polyethylenes, polypropylene, vinyls and nylons. (Plastics
Engineering, Handbook of The Society of the Plastics Industry, Inc., edited by Michael L.
Berins, 1991).
For thermoplastics, the identification of what are the "monomers and other starting
substances" is relatively simple. Petitions should be presented for all those components
deliberately added to a polymerisation medium, which will be integrated into the polymer.
The only permitted exceptions provided by Directive 2002/72/EC are:
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"The oligomers and natural or synthetic macromolecular substances as well as their mixtures, if the monomers
or starting substances required to synthesise them are included in the list;
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The mixtures of the authorised substances."
Examples:
1. If an ester derived from an acid and an alcohol contained in Section A of the
positive list is used as a monomer, it has to be the subject of a petition in order to be
listed as a new monomer. The ester has a toxicological profile different from that of
the acid and the alcohol from which it is formed. However, the technical dossier
accompanying the petition does not need to contain toxicological data if it is
demonstrated that metabolism completely hydrolyses the ester.
2. If oligomers formed from positive-listed monomers are used as a starting material,
they do not normally need to be listed. This is because they often have the same