Synergistic mixture

A synergistic mixture comprising from 1 to 99.9% by weight of at least one compound having at least one polycyclic phenolic compound which has up to 20 benzene rings per molecule and is obtained by reacting a tetrahydrobenzoxazine of the general formula XXVI

• wherein R19 is a hydrocarbyl radical which has from 1 to 3000 carbon atoms optionally interrupted by one or more selected from the group consisting of O, S and NR24, where R24 is a hydrogen atom or a C1- to C4-alkyl radical, wherein R20, R21, and R23 are each independently a hydrogen atom, a hydroxyl group or a hydrocarbyl radical which have in each case from 1 to 3000 carbon atoms optionally interrupted by on ore more selected from the group consisting of O, S and NR24,
• with one or more of the same or different phenols of the general formula XXVII
• wherein R25, R26, and R28 are each independently a hydrogen atom, a hydroxyl group or a hydrocarbyl radical which have in each case from 1 to 3000 carbon atoms optionally interrupted by one or more selected from the group consisting of O, S and NR24
• R22 is a hydrogen atom, a hydroxyl group, a hydrocarbyl radical which have in each case from 1 to 3000 carbon atoms optionally interrupted by on ore more selected from the group consisting of O, S and NR24, or a radical of formula Z″,
• R27 a hydrogen atom, a hydroxyl group, a hydrocarbyl radical which have in each case from 1 to 3000 carbon atoms optionally interrupted by on ore more selected from the group consisting of O, S and NR24, or a radical of the formula Z′″
• wherein R19, R20, R21, R23, R25, R26 and R28 are each as defined above, R25 may also be a radical derived from a tetrahydrobenzoxazine of the general formula XXVI, the substituent R33 is hydrogen or a radical derived from a tetrahydrobenzoxazine of the general formula XXVI, and R29 and R30 may be the same or different and are each hydrogen or a C1- to C10-alkyl radical,
• wherein R20 and R21 or R21 and R22 or R22 and R23 may also form a second tetrahydrooxazine ring with the —O—CH2—NR31—CH2— substructure attached to the benzene ring, or R20 and R21 and R22 and R23 may also form a second and a third tetrahydrooxazine ring with the —O—CH2—NR31—CH2— and —O—CH2—NR32—CH2— substructures attached to the benzene ring, where R31 and R32 are each independently hydrocarbyl radicals which have in each case from 1 to 3000 carbon atoms optionally interrupted by one or more selected from the group consisting of O, S and NR24,
• with the proviso that at least one of R19, R20, R21, R22, R23, R25, R26, R27, R28, R31 or R32 has from 13 to 3000 carbon atoms and the remaining substituents from the group of R19, R20, R21, R22, R23, R25, R26, R27, R28, R31 or R32, when they are hydrocarbyl radicals, have in each case from 1 to 20 carbon atoms
• (B) from 0.1 to 99% by weight of at least one sulfur-containing organic compound with antioxidant action,
• where the sum of the two components (A) and (B) adds up to 100% by weight.