Dodecanoic acid, 3-[[3-[[[2,2-dimethyl-3-[(1-oxododecyl)oxy]propylidene]amino]methyl]-3,5,5-trimethylcyclohexyl]imino]-2,2-dimethylpropyl ester

Endpoint summary

Description of key information

An acute eye irritation study with the test item SIKA Hardener LI was performed according to EU method B.5 and OECD guideline 405. SIKA Hardener LI was considered to not cause eye irritation in rabbits. The skin irritation study with SIKA Hardener LI was waived according to column 2 of REACH Annex XII section 8.1, as the acute dermal toxicity study (see section 7.2.1) did not indicate skin irritation up to the limit dose of 2000 mg/kg bw. 
Data from the hydrolysis products indicate that 2,2-Dimethyl-3-lauroyloxy-propanal is not irritating to skin and eye, but 3-aminomethyl-3,5,5-trimethylcyclohexylamine is classified as skin corrosive cat. 1B (see ECHA dissemination webpage). Nevertheless, data for the test item support the lack of irritating potential for SIKA Hardener LI and the effects of the amine are obviously not relevant for acute local effects in case of short time exposure to SIKA Hardener LI.

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

In a weight of evidence approach the biodegradation data form the parent molecule and the two primary hydrolysis products were assessed:

Eye irritation

An acute eye irritation study with the parent substance SIKA Hardener LI was performed according to EU method B.5 and OECD guideline 405. Potential irritation effects were assessed in three albino New Zealand White rabbits and test item exposures evaluated by the Draize method. The test item was placed into the conjunctival sac of the left eye of the animals. The untreated right eye served as control. 0.1 mL of the test item was used for the study in its pure state, as a single dose and were washed with physiological saline at the end of the treatment.

One hour after application of the test item SIKA Hardener LI, conjunctival redness and discharge was observed in all animals. At 24 hours after the treatment conjunctival redness was found in three animals. At 48 hours after the treatment, one animal showed conjunctival redness. At 72 hours after treatment, full recovery was observed in all animals and the study was terminated. The animal’s individual mean scores (considering readings at 24, 48 and 72 hours after the treatment) were as follows:

For animal 1: redness- 0.33, chemosis- 0. iris- 0, cornea opacity- 0

For animal 2: redness- 0.67, chemosis- 0. iris- 0.67 cornea opacity- 0

For animal 3: redness- 0.33, chemosis- 0. iris- 0.67, cornea opacity- 0

During the study the control eyes of the animals were symptom-free. The general state and the behaviour of the animals were normal throughout the study period. Thus, SIKA Hardener LI was considered to not cause eye irritation in rabbits.

The acute eye irritation study of the hydrolysis product 2,2-Dimethyl-3-lauroyloxy-propanal was performed in three New Zealand White rabbits. The irritation effect of the test item was evaluated according to the Draize method (OECD No.: 405, 2002). The test item was placed into the conjunctival sac of the left eye of each animal. The untreated right eye served as control. The treated eyes of the test animals were not washed out following the instillation of 0.1 mL of the test item, which was administered in pure state, in a single dose. The eyes were examined at 1, 24, 48, and 72 hours after the application. One hour after the single application of 2,2-Dimethyl-3-lauroyloxy-propanal into the eyes of the rabbits slight redness and moderately or severely increased discharge were observed in the eyes of the test animals. Chemosis, corneal and iris alterations were not found during the study. 24 hours after treatment in two animals slight redness was observed and in one case slightly increased discharge was noted. One animal became fully symptom-free by this time. 48 hours after the treatment every animal was symptom-free. 72 hours after the treatment the study was terminated, since no primary irritation symptoms occurred. The general state and the behaviour of animals were normal during the whole study. In conclusion, the test item 2,2-Dimethyl-3-lauroyloxy-propanal, applied to the rabbits' eye mucosa, caused irritant effects, which can be evaluated as fully reversible alterations within 48 h. According to the EU (DSD and GHS) criteria for classification and labelling requirements for dangerous substances and preparations the test item does not have to be classified and has no obligatory labelling requirement for eye irritation.

Isophorone diamine, the second hydrolysis product, was investigated for irritant effects on the eye and associated mucous membranes of 1 female rabbit according to OECD TG 405 (1981). The test substance was applied in a single dose of 0.1 ml into the conjuntival sac of the animal. The undiluted substance produced serious injury almost immediately after application (corrosive effects, opalescence). 24 hours after treatment conjunctiva showed necrosis. Due to the corrosive effect of the test material, only 1 animal was used and the experiment terminated after 24 hours.The lesions were not reversible. Therefore Isophorone diamine has to be considered to be corrosive and to cause irrivrsible damage to the eyes (see ECHA dissemination webpage).

Skin irritation

A study on skin irritation with the parent product SIKA Hardener LI was waived according to column 2 of REACH Annex XII section 8.1, as the acute dermal toxicity study (see section 7.2.1) did not indicate skin irritation up to the limit dose of 2000 mg/kg bw.

The acute skin irritation study of the hydrolysis product 2,2-Dimethyl-3-lauroyloxy-propanal was performed in New Zealand White rabbits. The irritation effect of the test item was evaluated according to the Draize method (OECD No.: 404, 2002). The test item was administered in a pure state, as a single dose of 0.5 mL, to the shaved skin of all experimental rabbits. The untreated skin of each animal served as control. After 4 hours any remaining test item was removed with water at body temperature. The animals were examined at 1, 24, 48 and 72 hours after the patch removal. No irritation symptoms (erythema and oedema) or other signs occurred after the patch removal and during the 72-hour observation period, so the study was terminated at the 72nd hour. During the study the behaviour and general state of animals were normal. The animal’s individual mean scores (considering readings at 24, 48 and 72 hours after patch removal) for erythema and oedema were 0.00, 0.00, 0.00 and 0.00, 0.00, 0.00 respectively. Thus, the classification of the test item 2,2-Dimethyl-3-lauroyloxy-propanal as a skin irritant is not required.

In a study with 6 adult rabbits 0.5 ml undiluted 3-aminomethyl-3,5,5-trimethylcyclohexylamine (Isophorone diamine), the second main hydrolysis product, was applied to the shorn dorsal skin of the animals ( intact and scarified) and covered with gauze and adhesive tape for 24 hours. The results were assessed at patch removal (24h) and 48 hr later (72 h), the skin had become hard and leatherlike. Edema scoring was not possible. Similar severity of effects was observed at both readings, i.e. there was no indication of reversibility within the observation period. In the study Isophorone diamine is described to be a severe irritant according to the scoring system used. Thus, under the conditions and according to the results of this study isophorone diamine has to be considered to be corrosive to the skin of rabbits (see ECHA dissemination webpage).

Justification for selection of skin irritation / corrosion endpoint:
only one (read across) study available

Justification for selection of eye irritation endpoint:
Two studies were used for a weight of evidence approach.

Justification for classification or non-classification

Based on the results of eye and skin irritation studies, SIKA Hardener LI is not classified and labelled as an eye or skin irritant according to Directive 67/548/EEC (DSD) and to Regulation (EC) No 1272/2008 (CLP).