abstract |
The invention relates to a composition characterised in that it comprises: a compound of the formula (I) in which R1, R2, R3 and R4 are identical or different and represent, independently from each other, a hydrogen atom, a methyl radical or an ethyl radical, A and B are identical or different and represent, independently from each other, a number between 0 and 10 with the proviso that the sum of A+B is higher than zero; and a compound of formula (II). |