The invention relates to an aqueous coating composition comprising a compound having reactive groups A, and a quaternary ammonium compound according to Formula I, II or IIIwhereinR1 is an alkyl, alkenyl, alkylaryl or arylalkyl group having from 5 to 50 carbon atomsR2 is a C1-C100 hydrocarbyl group, optionally containing heteroatomsR3 and R4 are alkylene groups having from 1 to 4 carbon atomsR5 and R6 are H or C1-C100 hydrocarbyl group, optionally containing heteroatomsR7 is a C1-C100 hydrocarbyl group, optionally containing heteroatomsR8 is a C1-C100 hydrocarbyl group, optionally containing heteroatomsR9 is H or a methyl groupZ is a substituent containing at least one reactive group B which is capable of reacting with the reactive group AX− is an aniony is 0 or 1a is 0 or 1 and the sum of y and a is 1 or 2 andm is an integer from 1 to 30, preferably between 1 and 10, or between 2 and 6n is an integer from 0-30, preferably between 1 and 10, or 2 and 6T is a monomer unitU is a monomer unitV is a C1-C100 hydrocarbyl group, optionally containing hetero atomsd is an integer between 1 and 5, preferably 1e is an integer between 1 and 1000, preferably between 5 and 100g is an integer between 1 and 100, preferably between 2 and 10h is an integer between 1 and 5, preferably 2 or 3.
