Coating composition for a subbing layer on a polyester film for light sensitive material

Polyester base film, having on at least one surface thereof a subbing coating which subbing coating consists essentially of components I and III or components II and III, wherein I, II and III are as follows:

• I - a polymer A having attached to its backbone carboxyl groups and/or groups which form carboxyl groups upon hydrolysis and
• a polymer B having attached to its backbone --SO.sub.3 X and/or --PO.sub.3 XY groups, wherein X and Y are identical or different and denote an alkali metal, ammonium, organic quaternary ammonium or hydrogen;
• II - a polymer A' having attached to its backbone carboxyl groups and/or groups which form carboxyl groups upon hydrolysis, and --SO.sub.3 X and/or --PO.sub.3 XY groups, wherein X and Y are identical or different and denote an alkali metal, ammonium, organic quaternary ammonium or hydrogen;
• III - an organic compound C having at least two free hydroxy groups,
• wherein the subbing does not comprise addition polymerizable compounds.

Polyester base film having on at least one surface thereof a primer coating and on at least one primer coating at least one aziridine-free subbing coating, which subbing coating comprises components I and III or components II and III, wherein components I, II and III are as follows:

• I - a polymer A having attached to its backbone carboxyl groups and/or groups which form carboxyl groups upon hydrolysis and a polymer B having attached to its backbone --SO.sub.3 X and/or --PO.sub.3 XY groups, wherein X and Y are identical or different and denote an alkali metal, ammonium, organic quaternary ammonium or hydrogen
• II - a polymer A' having attached to its backbone carboxyl groups and/or groups which form carboxyl groups upon hydrolysis, and --SO.sub.3 X and/or --PO.sub.3 XY groups, wherein X and Y are identical or different and denote an alkali metal, ammonium, organic quaternary ammonium or hydrogen
• III- an organic compound C having at least two free hydroxy groups,
• wherein the subbing coating does not comprise addition polymerizable compounds.