Composition for structural adhesive

A composition that can be used in a structural adhesive, said structural adhesive being formed from said composition and from a catalyst comprising a radical polymerization initiator of peroxide type, said composition comprising:

• (a) at least one methacrylate ester monomer selected from the group consisting of methyl methacrylate, ethyl methacrylate, tetrahydrofurfuryl methacrylate, phenoxyethyl methacrylate, isobornyl methacrylate, glycidyl ether methacrylate, benzyl methacrylate, cyclohexyl methacrylate, trimethylcyclohexyl methacrylate, hydroxyethyl methacrylate, and mixtures thereof,
• (b) a phosphate-ester-based adhesion promoter,
• (c) a cure accelerator comprising a tertiary amine of formula I:
• in which:
• the R3 group is a resonance electron-donating group comprising at least one aromatic group which is capable of forming, with the radical:
• and in combination with said radical polymerization initiator, a conjugated system exhibiting an absorption in the visible field of the electromagnetic spectrum, for generating coloration of said polymer during the reaction for polymerization of said monomer,
• the R1 and R2 groups are respectively and independently selected from the group consisting of:
• linear or branched C1 to C16 alkyl groups,
• C5 to C30 aryl or arylalkyl groups, and
• C2 to C15 alkylidene groups,
• said composition further comprising saccharin, and a metallic acrylate monomer (e).