Polymer registrations under K REACH
Polymers manufactured or imported into South Korea at more than 1 t/y are subject toregistration under K REACH, unless the polymer meets the PLC (Polymer of Low Concern)
criteria. There are basically two approaches to be considered when a substance meets thedefinition of a polymer under K REACH, one is a full registration and the other is applying foran exemption. If you are importing polymers to the Korean market, you should identify whichof the two approaches applies to your case. Polymers known as Polymer of Low Concern needto fulfill the conditions below (see chart) and are subject to exemption from registration. Youcan apply for an exemption in the K REACH IT system during the grace period, regardless ofthe quantity of the polymer, as long as you have pre-registered your polymer. If you are not a
pre-registration holder, you can apply for exemption prior to the manufacture or import of thepolymer.

To apply for an exemption, you must submit the required evidence to prove that the polymer
is exempted. The data requirements are as follows;••••

Substance name, CAS/KE-No., and content ratio(%) of the monomer compositions(Note: monomers less than 2(w/w)% are excluded.)
Analysis data showing Number Average Molecular Weight (Mn) and Molecular weight
distribution
Analysis GPC data on weight less than 1,000 of Mn and less than 500 of Mw
Content analysis data on the unreacted monomer

Definition of polymers and monomers under K REACH
The definitions of a polymer and monomer under K REACH are the same as under EU REACH.
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With a monomer being a substance which is capable of forming covalent bonds with asequence of additional like or unlike molecules under the conditions of the relevant polymerforming reaction used for the particular process. In other words, it is a substance which, via
the polymerization reaction, is converted into a repeating unit of the polymer sequence.
In order to determine whether the substance is a polymer, it needs to satisfy all the following
requirements; (Link)
Polymer definition under K-REACH
A.
B.

Requirement information

It shall be composed of molecules in which at least one kind

Monomer information, chemicalof monomer unit is continuously repeated.

structure

It shall represent the characteristic distribution of molecular(cweights in accordance with repetitive numbers of monomer

Analysis data (ex, GPC)

units in each molecule.
C.

D.

Its molecules that at least three monomer units form aAnalysis data (ex, GPC)

covalent bond with at least one monomer unit or other(Mn, Molecular weightreactants shall be at least 50 percent.

distribution)

Its molecules of the same molecular weight shall be not

Analysis data (ex, GPC)

more than 50 percent of the weight ratio.

(Molecular weight distribution)

Under K REACH, the definitions of existing chemical substances and new chemical substances
are also applied to polymers. Polymers which were distributed in Korea for commercial
purposes before February 2, 1991, are considered existing polymers. Otherwise, they areconsidered new polymers.
This means that the same grace period of existing chemical substances by tonnage band areapplied to polymers as well.

How to form a CICO for polymers?
CICOs (Chemical substance Information Communicative Organization, K-SIEF) are created foreach individual chemical substance and therefore also for polymers. With each polymer
available in a variety of different grades, the question on how to group polymers is a key pointin the registration of polymers under K REACH. According to the latest guidance on polymer
registration released by the Ministry of Environment (MoE) in September 2020, sameness of apolymer basically depends on the information of monomer(s) used in the polymerization. Thismeans that even if the Number Average Molecular Weight (Mn) and monomer content ofpolymers are not the same, a joint submission is possible when polymers are considered tohave the same monomers and reaction products. Nonetheless, the molecular structure andfunctional group should be considered for the hazard assessment of the polymers. There aresome cases when monomers are the same; the CAS numbers are different due to differencesin chemical structure. In this case, an extra CICO will be created, but a read-across approach
can be applied to minimize the number of new tests required.

Data requirements of a Joint submission for polymers
If data on physicochemical properties varies among the CICO members due to the variation inmonomer content and Mn values, individual physicochemical property data need to bePage 1 of 4

provided by each single member company of the CICO. Nonetheless the physicochemical
data can be provided jointly by grouping of the polymers based on Mn. For health andenvironmental properties the CICO members should choose a single data set for each
endpoint representative for the polymer. The guideline contains methods on how to determine
a representative data set for these end-points. With the exception of the before mentioned
requirements, the same toxicological, ecotoxiciological and risk assessment data as existingchemical substances need to be submitted for polymers.
Test material decisions will be a challenge for the registrants if a new study for registration isrequired. They can select several grades of the polymer to confirm the potential hazard inaccordance with the molecular weight. In general, a polymer with the lowest Mn is considered
the most harmful, but this is only applicable when the polymer does not have any other harmful
elements, functional groups, or counter ions (metal ion). If the polymer has any of those, anequivalent mass of the harmful element and functional group need to be examined. The newguidance implies that the reactivity of a polymer is affected by the number of monomer units
participating in the polymerization, therefore, the equivalent weight of the hazardous
components need to be identified and registrants should select conservatively appropriate test
material for their polymer. This will require active data sharing and discussions within the CICO.

How to prepare a SID report for polymers?
The new polymer guidance contains detailed information on the measurement, method, andsolvent etc. for substance identification. For example, the recommended analysis methods formolecular weight distribution are GPC, osmotic pressure method, light scattering method andintrinsic viscosity method. When the molecular weight of each molecule is low and it is difficult
to separate the low molecular weight polymer with GPC, HPLC measurements are allowed as
an alternative.

What about NLP (No Longer Polymers) with the same monomers as the polymer?
The guidance specifies that if a) all uses and exposure scenarios of the polymer and NLP are
identical, b) it is not a cationic polymer and, c) unreacted monomers being on the list ofhazardous substances, or considered a SVHC, or a non-phase-in substance are present at
less than 0.1% in the polymer, the polymer does not have to be registered separately from theNLP. The potential registrants should register the substance with a combined tonnage of both
NLP and polymer. This is considered a very cost-effective strategy, as the NLP has alreadybeen registered under EU REACH. This means data sets for a full registration are alreadyavailable. It will also help registrants avoid unnecessary animal testing. To benefit from thisapproach, registrants need to justify that the same hazard classification is applicable to both
NLP and polymer. The minimum information required to predict the hazard properties of apolymer are toxicokinetic data as deduced from physicochemical properties and the molecularstructure analysis. Toxicokinetic data are not mandatory requirements, but it may be helpful tomake a robust justification through predicting the behavior of polymer molecules.

What can be challenges for polymer registrants
The differences between K REACH and other global regulations on polymers will cause
additional burden on many registrants. Identifying substances that fall under the polymer

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definition and separate them into groups which are subject for exemption and for registration
can be a challenge. Several parts of the polymer guidance from the Korean government are
unclear on risk assessment and the guidance may not be sufficient to cover all the various use
cases. Collecting use information on polymers will be a challenge due to the wide applicationof polymers. It will also not be easy for registrants who have already experienced monomer
registrations under EU REACH, as they have never addressed polymer use information andwill have signification data gaps.

Authors:
JI YEONG KIM, Strategic Business Development Asia, Regulatory Affairs, SCC GmbH
JISU YANG, Team Manager, TSafeG
JIMIN PARK, Team Manager, TSafeG

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