Additive for UV-sunscreen preparations

1. A process for boosting ultraviolet (UV) absorption of a UV filter in a UV sunscreen composition comprising adding to the sunscreen composition polymeric particles comprising at least one chromophore having a UV absorption maximum at λ max ≧275 nm covalently bound thereto, wherein the chromophore comprises a moiety according to general formula (III)

wherein ┤ denotes a covalent bond to the polymeric particle, and

wherein,

R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 are independently selected from —H, —F, —Cl, —CN, —CF 3 , —N 3 , —NO, —NO 2 , —OH, —OCO—C 1 -C 6 -alkyl, —CO 2 H, —SO 3 H, —CO 2 —C 1 -C 6 -alkyl, —S(O) k —C 1 -C 6 -alkyl wherein index k is 0, 1 or 2; —CO—C 1 -C 6 -alkyl, —NH 2 , —NH—C 1 -C 6 -alkyl, —N(C 1 -C 6 -alkyl) 2 , —NHCO—C 1 -C 6 -alkyl, —C 1 -C 20 -alkyl wherein optionally 1, 2 or 3 methylene groups are replaced by —O—, —C 3 -C 7 -cycloalkyl; methenyl which may optionally be substituted with R a and R b independently selected from —Cl, —CN, —CO 2 —C 1 -C 6 -alkyl and —O—C 1 -C 6 -alkyl; —C 2 -C 20 -alkenyl, —C 2 -C 20 -alkynyl, —C 6 -C 10 -aryl, —C 3 -C 9 -heteroaryl, —C 7 -C 20 -alkylaryl wherein optionally 1, 2 or 3 methylene groups are replaced by —O—, —CO—C 6 -C 10 -aryl or —C 5 -C 20 -alkylheteroaryl,

L is a linker unit,

Y 2 is —O—; —CO—; —CO 2 —; —OCO—; —NR′CO— wherein R′ is —H or —C 1 -C 6 -alkyl; —C 1 -C 6 -alkylene-; or -phenylene- substituted with R 9 , R 10 , R 11 and R 12 wherein each of R 9 , R 10 , R 11 and R 12 is H,

n is an integer of 0 to 10, and

X is —S—, —O— or —NR′″—, wherein R′″ is —H or —C 1 -C 20 -alkyl.

2. The process according to claim 1 , wherein λ max ≧290 nm.

3. The process according to claim 1 , wherein the chromophore comprises a moiety selected from the group consisting of acrylates, p-aminobenzoates, camphor derivatives, cinnamates, benzophenones, benzalmalonic acid esters, 2-(4-ethoxy anilinomethylene)-propandioic esters, imidazole derivatives, salicylates, triazone derivatives, benzotriazol derivatives, dibenzoylmethanes, amino substituted hydroxybenzophenones, phenyl-benzimidazoles, anthranilates, phenyl-benzoxazoles, 1,4-dihydropyranes and 1,4-dihydropyridine derivatives.

4. The process according to claim 1 , wherein the polymeric particles have an average particle size that is within the range of from 0.01 to 5 μm.

5. The process according to claim 1 , wherein index n is 1 or 2 and L is —C 2 -C 6 -alkylene-O— or —C 2 -C 6 -alkylene-NH—, and wherein the carbon atoms of each alkylene-group may be optionally substituted with one, two or three hydroxy groups.

6. The process according to claim 1 , wherein index n is 0.