An additive mixture containing at least one high molecular weight triazine compound of the formula or a mixture of at least one high molecular weight triazine compound of the formula and at least one high molecular weight triazine compound of the formula, wherein b 1 is a number from 1 to 20; the radicals R 1 independently of one another are hydrogen, C 1 -C 8 alkyl, O·, - OH, -CH 2 CN, C 1 -C 18 alkoxy, C 5 -C 12 cycloalkoxy, C 3 -C 6 alkenyl, C 7 -C 9 phenylalkyl unsubstituted or substituted on the phenyl by 1, 2 or 3 C 1 -C 4 alkyl; or C 1 -C 8 acyl; R 2 is C 2 -C 18 alkylene, C 5 -C 7 cycloalkylene or C 1 -C 4 alkylenedi(C 5 -C 7 cycloalkylene); R 3 and R 4 independently of one another are hydrogen, C 1 -C 12 alkyl, C 5 -C 12 cycloalkyl unsubstituted or substituted by 1, 2 or 3 C 1 -C 4 alkyl; phenyl unsubstituted or substituted by 1, 2 or 3 C 1 -C 4 alkyl; C 7 -C 9 phenylalkyl unsubstituted or substituted on the phenyl by 1, 2 or 3 C 1 -C 4 alkyl; or a group of the formula (Ia) or R 3 and R 4, together with the nitrogen atom to which they are linked, form a 5-to 10-membered heterocyclic ring; wherein b 2 is a number from 1 to 20; the radicals X 1 independently of one another are hydrogen, C 1 -C 8 alkyl, O·, - OH, -CH 2 CN, C 1 -C 18 alkoxy, C 5 -C 12 cycloalkoxy, C 3 -C 6 alkenyl, C 7 -C 9 phenylalkyl unsubstituted or substituted on the phenyl by 1, 2 or 3 C 1 -C 4 alkyl; or C 1 -C 8 acyl; the radicals Y 1 independently of one another are hydrogen, C 1 -C 12 alkyl, C 5 -C 12 cycloalkyl unsubstituted or substituted by 1, 2 or 3 C 1 -C 4 alkyl; phenyl unsubstituted or substituted by 1, 2 or 3 C 1 -C 4 alkyl; C 7 -C 9 phenylalkyl unsubstituted or substituted on the phenyl by 1, 2 or 3 C 1 -C 4 alkyl; or a group of the formula (IIa); the radicals Z 1 independently of one another are C 2 -C 18 alkylene, C 5 -C 7 cycloalkylene or C 1 -C 4 alkylenedi(C 5 -C 7 cycloalkylene); and at least one heat reflecting interference pigment, which is in the form of platelets coated with one or more metal oxides, wherein the platelets contain layered silicate, glass or ceramic. at least one high molecular weight triazine compound of the formula or a mixture of at least one high molecular weight triazine compound of the formula and at least one high molecular weight triazine compound of the formula, wherein b 1 is a number from 1 to 20; the radicals R 1 independently of one another are hydrogen, C 1 -C 8 alkyl, O·, - OH, -CH 2 CN, C 1 -C 18 alkoxy, C 5 -C 12 cycloalkoxy, C 3 -C 6 alkenyl, C 7 -C 9 phenylalkyl unsubstituted or substituted on the phenyl by 1, 2 or 3 C 1 -C 4 alkyl; or C 1 -C 8 acyl; R 2 is C 2 -C 18 alkylene, C 5 -C 7 cycloalkylene or C 1 -C 4 alkylenedi(C 5 -C 7 cycloalkylene); R 3 and R 4 independently of one another are hydrogen, C 1 -C 12 alkyl, C 5 -C 12 cycloalkyl unsubstituted or substituted by 1, 2 or 3 C 1 -C 4 alkyl; phenyl unsubstituted or substituted by 1, 2 or 3 C 1 -C 4 alkyl; C 7 -C 9 phenylalkyl unsubstituted or substituted on the phenyl by 1, 2 or 3 C 1 -C 4 alkyl; or a group of the formula (Ia) or R 3 and R 4, together with the nitrogen atom to which they are linked, form a 5-to 10-membered heterocyclic ring; wherein b 2 is a number from 1 to 20; the radicals X 1 independently of one another are hydrogen, C 1 -C 8 alkyl, O·, - OH, -CH 2 CN, C 1 -C 18 alkoxy, C 5 -C 12 cycloalkoxy, C 3 -C 6 alkenyl, C 7 -C 9 phenylalkyl unsubstituted or substituted on the phenyl by 1, 2 or 3 C 1 -C 4 alkyl; or C 1 -C 8 acyl; the radicals Y 1 independently of one another are hydrogen, C 1 -C 12 alkyl, C 5 -C 12 cycloalkyl unsubstituted or substituted by 1, 2 or 3 C 1 -C 4 alkyl; phenyl unsubstituted or substituted by 1, 2 or 3 C 1 -C 4 alkyl; C 7 -C 9 phenylalkyl unsubstituted or substituted on the phenyl by 1, 2 or 3 C 1 -C 4 alkyl; or a group of the formula (IIa); the radicals Z 1 independently of one another are C 2 -C 18 alkylene, C 5 -C 7 cycloalkylene or C 1 -C 4 alkylenedi(C 5 -C 7 cycloalkylene); and b 1 is a number from 1 to 20; the radicals R 1 independently of one another are hydrogen, C 1 -C 8 alkyl, O·, - OH, -CH 2 CN, C 1 -C 18 alkoxy, C 5 -C 12 cycloalkoxy, C 3 -C 6 alkenyl, C 7 -C 9 phenylalkyl unsubstituted or substituted on the phenyl by 1, 2 or 3 C 1 -C 4 alkyl; or C 1 -C 8 acyl; R 2 is C 2 -C 18 alkylene, C 5 -C 7 cycloalkylene or C 1 -C 4 alkylenedi(C 5 -C 7 cycloalkylene); R 3 and R 4 independently of one another are hydrogen, C 1 -C 12 alkyl, C 5 -C 12 cycloalkyl unsubstituted or substituted by 1, 2 or 3 C 1 -C 4 alkyl; phenyl unsubstituted or substituted by 1, 2 or 3 C 1 -C 4 alkyl; C 7 -C 9 phenylalkyl unsubstituted or substituted on the phenyl by 1, 2 or 3 C 1 -C 4 alkyl; or a group of the formula (Ia) b 2 is a number from 1 to 20; the radicals X 1 independently of one another are hydrogen, C 1 -C 8 alkyl, O·, - OH, -CH 2 CN, C 1 -C 18 alkoxy, C 5 -C 12 cycloalkoxy, C 3 -C 6 alkenyl, C 7 -C 9 phenylalkyl unsubstituted or substituted on the phenyl by 1, 2 or 3 C 1 -C 4 alkyl; or C 1 -C 8 acyl; the radicals Y 1 independently of one another are hydrogen, C 1 -C 12 alkyl, C 5 -C 12 cycloalkyl unsubstituted or substituted by 1, 2 or 3 C 1 -C 4 alkyl; phenyl unsubstituted or substituted by 1, 2 or 3 C 1 -C 4 alkyl; C 7 -C 9 phenylalkyl unsubstituted or substituted on the phenyl by 1, 2 or 3 C 1 -C 4 alkyl; or a group of the formula (IIa); at least one heat reflecting interference pigment, which is in the form of platelets coated with one or more metal oxides, wherein the platelets contain layered silicate, glass or ceramic.