Patent ID: 7413599

Claim:
A pearlescent pigment with a platelet-shaped substrate comprising metal oxide and having a first and a second protective layer, said metal oxide having a refractive index of greater than 1.8, there being on the platelet-shaped substrate a first protective layer comprising cerium oxide, cerium hydroxide, or a mixture thereof and a second protective layer of SiO 2 , applied to which is an organic chemical aftercoat comprising at least one silane having at least one functional bond group and at least one silane without a functional bond group, it being possible for metal oxide layers other than cerium oxide and SiO 2 to be disposed between the first and the second protective layer, wherein the silane without a functional bond group is an alkylsilane having the structural formula (I): R (4-z) Si(X) z (I) where z is an integer from 1 to 3; R is a substituted or unsubstituted, unbranched or branched alkyl chain having 10 to 22 carbon atoms, and X is a halogen and/or alkoxy group, or wherein the silane without a functional bond group has the structural formula (II): (R 1 —X-[A-Y] n —B) (4-z) Si(OR 2 ) z (II) where n=1 to 100; z is an integer from 1 to 3; R 1 is a straight- or branched-chain alkyl having 1 to 12 carbon atoms, which may be substituted by halogens; an aryl having 6 to 12 carbon atoms: or an aryl having 6 to 12 carbon atoms, which is substituted by alkyl having 1 to 6 carbon atoms, halogen atoms, or a combination thereof; R 2 is straight or branched-chain alkyl having 1 to 6 carbon atoms; A and B independently of one another are a divalent group consisting of straight- or branched-chain alkylene having 1 to 12 carbon atoms; an arylene having 6 to 12 carbon atoms; or an arylene having 6 to 12 carbon atoms, which is substituted by alkyl having 1 to 6 carbon atoms, halogen atoms, or a combination thereof; and X and Y independently of one another are O or S.