A polysiloxane-polycarbonate block cocondensate derived from a continuous melt transesterification process comprising polysiloxane blocks of the formula in which R 1 is H, Cl, Br or C 1 to C 4 -alkyl, preferably H or methyl, and especially preferably H, R 2 and R 3 are the same or different and each independently from one another selected from aryl, C 1 to C 10 -alkyl and C 1 to C 10 -alkylaryl, preferably R 2 and R 3 are methyl, X is a single bond, -CO-, -O-, C 1 - to C 6 -alkylene, C 2 to C 5 -alkylidene, C 5 to C 12 -cycloalkylidene or C 6 to C 12 -arylene which may optionally be fused to further aromatic rings containing heteroatoms, X preferably being a single bond, C 1 to C 5 -alkylene, C 2 to C 5 -alkylidene, C 5 to C 12 -cycloalkylidene, -O- or -CO-, X more preferably being a single bond, isopropylidene, C 5 - to C 12 -cycloalkylidene or oxygen, and most preferably isopropylidene, n is a number from 1 to 500, preferably from 10 to 400, especially preferably from 10 to 100, most preferably from 20 to 60, m is a number from 1 to 10, preferably from 1 to 6, especially preferably from 2 to 5, and p is 0 or 1 and the value of n times m is preferably between 12 and 400, more preferably between 15 and 200; and polycarbonate blocks having recurring units of the formula where Z is C1 to C8 alkylidene, S, SO 2 or a single bond, R4 and R5 are mutually independently a substituted or unsubstituted C1 to C18 alkyl moiety, halogen or H, preferably methyl, ethyl, propyl, butyl, phenyl, Cl, Br, especially preferably H; and r and s is mutually independently 0, 1, or 2; wherein the polysiloxane-polycarbonate block cocondensate has a siloxane domain distribution (diameter of siloxane domains) from 200 nm to 1 μm measured by atomic force microscopy and light microscopy which is in the range of 0.01 % - 2.5 %, based on the total number of siloxane domains. polysiloxane blocks of the formula in which R 1 is H, Cl, Br or C 1 to C 4 -alkyl, preferably H or methyl, and especially preferably H, R 2 and R 3 are the same or different and each independently from one another selected from aryl, C 1 to C 10 -alkyl and C 1 to C 10 -alkylaryl, preferably R 2 and R 3 are methyl, X is a single bond, -CO-, -O-, C 1 - to C 6 -alkylene, C 2 to C 5 -alkylidene, C 5 to C 12 -cycloalkylidene or C 6 to C 12 -arylene which may optionally be fused to further aromatic rings containing heteroatoms, X preferably being a single bond, C 1 to C 5 -alkylene, C 2 to C 5 -alkylidene, C 5 to C 12 -cycloalkylidene, -O- or -CO-, X more preferably being a single bond, isopropylidene, C 5 - to C 12 -cycloalkylidene or oxygen, and most preferably isopropylidene, n is a number from 1 to 500, preferably from 10 to 400, especially preferably from 10 to 100, most preferably from 20 to 60, m is a number from 1 to 10, preferably from 1 to 6, especially preferably from 2 to 5, and p is 0 or 1 and the value of n times m is preferably between 12 and 400, more preferably between 15 and 200; R 1 is H, Cl, Br or C 1 to C 4 -alkyl, preferably H or methyl, and especially preferably H, R 2 and R 3 are the same or different and each independently from one another selected from aryl, C 1 to C 10 -alkyl and C 1 to C 10 -alkylaryl, preferably R 2 and R 3 are methyl, X is a single bond, -CO-, -O-, C 1 - to C 6 -alkylene, C 2 to C 5 -alkylidene, C 5 to C 12 -cycloalkylidene or C 6 to C 12 -arylene which may optionally be fused to further aromatic rings containing heteroatoms, X preferably being a single bond, C 1 to C 5 -alkylene, C 2 to C 5 -alkylidene, C 5 to C 12 -cycloalkylidene, -O- or -CO-, X more preferably being a single bond, isopropylidene, C 5 - to C 12 -cycloalkylidene or oxygen, and most preferably isopropylidene, n is a number from 1 to 500, preferably from 10 to 400, especially preferably from 10 to 100, most preferably from 20 to 60, m is a number from 1 to 10, preferably from 1 to 6, especially preferably from 2 to 5, and p is 0 or 1 and the value of n times m is preferably between 12 and 400, more preferably between 15 and 200; and polycarbonate blocks having recurring units of the formula where Z is C1 to C8 alkylidene, S, SO 2 or a single bond, R4 and R5 are mutually independently a substituted or unsubstituted C1 to C18 alkyl moiety, halogen or H, preferably methyl, ethyl, propyl, butyl, phenyl, Cl, Br, especially preferably H; and r and s is mutually independently 0, 1, or 2; wherein the polysiloxane-polycarbonate block cocondensate has a siloxane domain distribution (diameter of siloxane domains) from 200 nm to 1 μm measured by atomic force microscopy and light microscopy which is in the range of 0.01 % - 2.5 %, based on the total number of siloxane domains. Z is C1 to C8 alkylidene, S, SO 2 or a single bond, R4 and R5 are mutually independently a substituted or unsubstituted C1 to C18 alkyl moiety, halogen or H, preferably methyl, ethyl, propyl, butyl, phenyl, Cl, Br, especially preferably H; and r and s is mutually independently 0, 1, or 2;