Antimicrobial composition comprising a polyimide

An aqueous antimicrobial cleaning composition comprising:

• i) from 0.02% to 2.50% by weight of the composition of a biocidal agent selected from the group consisting of quaternary ammonium compounds, chlorohexidine salts, polymeric biguanides, tertiary alkyl amines and mixtures thereof;
• and
• ii) a polyimide.
• wherein the polyimide comprises at least one structural unit (A1), at least one structural unit (A2), at least one structural unit (A3), and optionally one additional structural unit (A4)
• wherein
• R1 stands for an optionally heterofunctionalized alkyl radical;
• R2 stands for an optionally heterofunctionalized alkyl radical other than R1;
• and
• R3, independently of one another, stands for H, or an optionally heterofunctionalized alkyl radical other than R1 and R2.