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Administrative data

Link to relevant study record(s)

Description of key information

Based on the reactive nature of SIKA Hardener LI and its limited stability in water-based systems, bioaccumulation is not likely to occur. Orally consumed hardener is most rapidly hydrolysed to aldehyde and polyamine, with the reaction being acid catalysed. Even though the degradation products might be absorbed and become bioavailable, toxicity is low and bioconcentration rather unlikely. Absorbed or bioavailable degradation products are probably excreted, either in original form or further metabolised, prior to elimination via urine or bile. 

Key value for chemical safety assessment

Bioaccumulation potential:
no bioaccumulation potential

Additional information

General

SIKA Hardener LI belongs to a class of polyaldimine compounds used as hardeners for polyurethane moisture hardening preparations. The preparations are used as adhesive and sealant in the production of transport vehicle modules. On contact with water, the hardening process is initiated and the hardener rapidly hydrolysed. Hydrolysis products formed are the aldehyde 2,2-dimethyl-3-lauroyloxy-propanal and corresponding polyamine. The hardener and polyurethane mass react and become chemically bound in the polymer matrix, irreversibly integrating the amine component and the polyamine and to some extend the aldehyde. Due to the use of the compound, SIKA Hardener LI has a very limited stability in water, as it needs to rapidly react upon contact with water. Thus, determination of its partition coefficient or water solubility is technically not feasible. The theoretical partition coefficient and water solubility ranges were calculated, taking the varying oligomere chain lengths into account.

Toxicokinetic assessment

Based on molecular structure and physical-chemical properties, bioaccumulation of SIKA Hardener LI is not likely to occur. Dermal and inhalation uptake can be practically exclued. Orally consumed hardener is very fast hydrolysed to aldehyde and polyamine, in the acid environment of the stomach. Even though the degradation products might be absorbed and become bioavailable, toxicity is low and bioconcentration rather unlikely. Absorbed or bioavailable degradation products are probably excreted, either in original form or further metabolised, prior to elimination via urine or bile. Formation of toxic metabolites is unlikely, based on the results of the subacute toxicity study and two in vitro studies using isolated S9 fractions. However, a subchronic oral toxicity study indicated toxicity as a test item related effect was observed at 1000 mg/kg bw (changes in spleen weights in female rats), resulting in a NOAEL of 300 mg/kg bw.