Page 16 - CITDBooklet

Guide on the application of REACH Regulation

In other words:
■ >50% of the weight for that substance must consist of polymer molecules, however
■ The amount of polymer molecules representing the same molecular weight must be
<50 weight % of the substance.

Let us consider a Phenol ethoxylate.
C6H5 –O--(CH2-CH2-O)n – H

Here for this substance to be considered as a polymer following conditions need to be met
1. The product should contain more than 50% of phenol ethoxylate molecules. [An aqueous
formulation with less than 50% content of phenol ethoxylate will not be considered as
polymeric substance];

2. Degree of ethoxylation should be n≥3. [More than or equal to at least 3 repetitive units];

3. The molecular weight distribution should vary and not more than 50% of the molecules
should have same molecular weight (same n). This can be further explained by an
example shown in table below.

Table below shows 3 variants of a substance having different molecular weight distributions.

n=1 - 40% 5%
n=2 10% 20% 30%
n=3 85% 15% 20%
n=4 5% 12% 30%
n=5 8% 20%
n=6 - 5% 10%
n=7 - 5%
Sum - - 100%
100% 100% Polymer
No Polymer No Polymer

Polymer content is 90% [n=3 + n=4] as against requirement of >50% [neglect
n=2].

However this is not a polymer, as molecules with same molecular weight
n=3=85% whereas number of molecules with same molecular weight must
be <50%.

Polymer content is 40% [n=3+n=4+n=5+n=6] [neglect n=1; n=2] as against
requirement of >50%. This is not a polymer, though molecular weight
distribution meets requirements of molecules with same molecular weight
not to exceed 50%.

Polymer content is 85% [n=3+n=4+n=5+n=6+n=7][neglect n=1 and n=2]
(required > 50%).

Molecular weight distribution OK as n=3; n=4; n=5; n=6 and n=7 are all below
50% each.

Both conditions of polymer content and molecular weight distribution
satisfied.

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