Reaction products of 2,2'-[(1-methylethylidene)bis(4,1-phenyleneoxymethylene)]bisoxirane with maleic anhydride and methacrylic acid

Endpoint summary

Additional information

Modified Small Vinyl Ester is a slightly water soluble, highly viscous prepolymer, which is placed on the market as an approximately 50% solution in a reactive diluent for industrial use only. When exposed to light, Modified Small Vinyl Ester will polymerise and bind all Modified Small Vinyl Ester and most of the reactive diluent covalently in an extremely stable and highly water insoluble polymer with very low bioavailability in water and soil. See the CSA for further details.

Stability

Testing of hydrolysis of Modified Small Vinyl Ester was performed according to OECD Guideline method 111 and EC test method C.7 and compliant with GLP. The determination half-life times of Modified Small Vinyl Ester is based on the hydrolysis half-life times for bisGMA and its monomaleic adduct, which are the main constituents of Modified Small Vinyl Ester, amounting ca. 57.5% and 14.5%, respectively. The ultimate hydrolysis products are estimated to be the same from these two compounds, except for maleic acid released from monomaleic adduct of bisGMA. The hydrolysis half-life times are similar for the two compounds at pH=4 and pH=9, but at pH=7 the half-life time of monomaleic adduct of bisGMA is 2-3 times that of bisGMA at the lowest test temperatures (20-50 °C). At the highest test temperature (60/70 °C) the hydrolysis half-life time is approximately the same. The hydrolysis half-life times were found to be strongly correlated to temperature and pH. BisGMA will hydrolyse more rapidly than its monomaleic adduct. At pH=7 and 20 °C, after approximately 85 days, i.e. 3 half-life times for bisGMA and 1 half-life time for its monomaleic adduct, the remainder of the two compounds amounts approximately 9%, i.e. 13% of the original amount of bisGMA and 50% of the original amount of monomaleic adduct of bisGMA. The highest obtained half-life value was used as a key value for the chemical safety assessment, i.e. 85 days at 20 °C (at pH=7).

Biodegradation

Modified Small Vinyl Ester was evaluated to be not readily biodegradable. Ready biodegradability of Modified Small Vinyl Ester was assessed conducting a modified sturm test compliant with GLP. Modified Small Vinyl Ester did not inhibit microbial activity in the toxicity control. The relative biodegradation values calculated from the measurements performed during the test period revealed no significant biodegradation of Modified Small Vinyl Ester. This result may be due to low bioavailability.

Water simulation testing is waived in accordance with REACH Annex IX, section 9.2.1.2, column 2. Modified Small Vinyl Ester is only slightly soluble in water. Modified Small Vinyl Ester is a highly viscous prepolymer, which is placed on the market as an approximately 50% solution in a reactive diluent. Modified Small Vinyl Ester will polymerise to an insoluble polymer. Exposure of the aquatic environment is unlikely. See the CSA for further details.

Soil simulation testing is waived in accordance with REACH Annex IX, section 9.2.1.3 column 2, because Modified Small Vinyl Ester is a highly viscous prepolymer, which is placed on the market as an approximately 50% solution in a reactive diluent. Modified Small Vinyl Ester will polymerise to an insoluble polymer with very low bioavailability in soil. Modified Small Vinyl Ester is unlikely to reach soil thus direct and indirect exposure of soil is judged to be unlikely. See the CSA for further details.

Bioaccumulation

Testing for aquatic bioaccumulation of Modified Small Vinyl Ester is waived in accordance with REACH Annex IX, section 9.3.2, column 2. Modified Small Vinyl Ester is a highly viscous prepolymer, which is placed on the market as an approximately 50% solution in a reactive diluent. Modified Small Vinyl Ester will polymerise to an insoluble polymer with very low bioavailability in water. Modified Small Vinyl Ester is unlikely to reach water, thus direct and indirect exposure of water is judged to be unlikely. Bioaccumulation in aqueous species is unlikely. See the CSA for further details.

Transport and distribution

The Koc value of Modified Small Vinyl Ester is calculated to 14,600 (log Koc is 4.16) at 35 °C based on the experimental data for the two main constituents of Modified Small Vinyl Ester (bisGMA, ca. 57.5% and its monomaleic adduct, ca. 14.5%). The high values indicate that Modified Small Vinyl Ester will bind tightly to soils and sediments and thus, reduce overall exposure potential. Monomaleic adduct of bisGMA is an organic acid that is fully ionised at neutral pH. It has a low Koc value (18) at this pH and may not bind tightly to soils and sediment. However, Modified Small Vinyl Ester is a highly, viscous liquid that is marketed as an approximately 50% solution in a reactive diluent. Modified Small Vinyl Ester will polymerise to an insoluble polymer and become immobilised in the environment.