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Description of key information

Amine synergist is mainly used as a radiation curing resin for coatings and inks. The REACH-related applications of this substance are in industrial and professional settings. Section 9 details the lifecycle of amine synergist and indicates potential exposure routes. Since the substance is in liquid form, dermal or eye exposure may occur as a result of spills or splashes during transport, process or handling. Because of its low vapour pressure, exposure via inhalation is expected to be minimal under ambient conditions but may occur in situations where the material aerosolizes or volatilizes during use or handling (e.g. spraying or exposure to elevated temperatures/pressure).

No published data could be found on the toxicokinetics of amine synergist. However, as per REACH guidance document R7.C, information on absorption, distribution, metabolism and excretion may be deduced from the physico-chemical properties, including:

- Water solubility

- Partition coefficient

- Vapour pressure

- Molecular weight

Given the small molecular weight (ca. 319 – 518 g/mol) and the moderate to high water solubility of the main constituents of amine synergist, they are likely to be absorbed into the organisms after oral exposure. This is supported by data on certain of the ‘building block substances’ of amine synergist, i.e. tripropylene glycol (TPG), tripropylene glycolmonoacrylate (TPGMA) and diethylamine (DEA).

A study conducted in rat with 14C-labelled TPG shows thatthe substance is rapidly absorbed if administered by oral gavage(REACH registration of TPG [1]). The greatest percentage of the administered radiolabeled dose was recovered in the urine, with most of the remaining radioactivity exhaled as14CO2. A small amount was recovered in the feces and the final cage wash. Approximately 10% of the radiolabelled dose was recovered from tissues and carcass, in particular liver and kidneys. TPG was extensively metabolized, with only little recovered as unmetabolized parent compound in the urine, the rest being acid-labile conjugates of TPG, free and acid-labile conjugates of dipropylene glycol (DPG), and free and acid-labile conjugates of monopropylene glycol (MPG). Little is known about the further metabolism of TPG, but it appears likely that it may also enter into intermediary metabolism MPG formation. It is noteworthy that a large fraction of the14C-TPG dose was catabolized all the way to 14CO2, indicating considerable breakdown. The data indicate TPG is readily biotransformed to DPG and MPG which is then further oxidized to CO2.

Data available for the appropriate read-across substance 2-hydroxyethyl acrylate (HEA) suggest that, once TPGMA is absorbed, it is also rapidly metabolised and eliminated from the body (REACH registration of TPGMA)[2]. The same findings apply to DEA (REACH registration of DEA [3]).

Based on the criteria summarised in Table R.7.12-3 of guidance document R7.C, dermal absorption of amine synergistis expected to be slowed due to binding to skin of the acrylate group. Dermal absorption of TPG is estimated at 0.1% based on animal testing (REACH registration of TPG2).

Given the very low to moderate log Kow of the components and hydrolysis products (-2.44 to 2.5) and the indication for oral absorption, systemic uptakeafterinhalationexposure is possible, although this would occur only when aerosol or vapour is created under particular conditions (e.g. spraying, elevated temperature/pressure). Under normal use conditions, exposure via vapour is unlikely given the low vapour pressure of the substance (0.0136 Pa at 20°C).


[1] REACH registration of TPG:REACH registration of TPG (EC number 246-466-0):

[2] REACH registration of TPGMA EC number 247-118-0):

[3] REACH registration of DEA (EC number 203-868-0):

Key value for chemical safety assessment

Bioaccumulation potential:
low bioaccumulation potential

Additional information