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,
• (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:
• linear or branched C1 to C16 alkyl groups,
• C5 to C30 aryl or arylalkyl groups,
• C2 to C15 alkylidene groups,
• wherein said composition further comprises a metallic acrylate monomer (e) and a mixture of 2-hydroxyethyl methacrylate (HEMA) and 2-hydroxypropyl methacrylate (HPMA).