Single layer film and hydrophilic material comprising the same

A method for producing a multilayer body, wherein the multilayer body comprises a single layer film formed on at least one side of a substrate layer, the method comprising:

• forming on at least one side of a substrate layer a coating layer comprising
• a composition containing a compound (I) represented by the general formula (1) mentioned below,
• a compound (II) having two or more (meth)acryloyl groups in a molecule at a molar ratio of 15:1 to 1:30, and
• a solvent having a solubility parameter of 9.5 (cal/cm3)1/2 or more, drying the composition whereby the amount of residual solvent is 10% or less, and polymerizing the coating layer to form the single layer film formed on at least one side of a substrate layer,
• the single layer film of the obtained polymer having at least one anionic hydrophilic group selected from a sulfonic acid group, a carboxyl group and a phosphate group distributed in such a manner that an anion concentration ratio (Sa/Da) of an anion concentration at a surface (Sa) to an anion concentration at a deep part (Da) is 1.1 or more,
• General formula (1)
• [Formula 43]
• [X]s[M1]l[M2]m (1)
• wherein, s represents 1 or 2, l represents 1 or 2, and m represents 0 or 1, M1 and M2 may be the same or different and represent a hydrogen ion, an ammonium ion, an alkali metal ion, or an alkaline earth metal ion, X represents one kind selected from the hydrophilic groups represented by the following general formulae (1-1) to (1-4),
• (in the formulae, J and J′ may be the same or different and represent H or CH3;
• n represents 0 or 1;
• R and R′ may be the same or different, represent an aliphatic hydrocarbon group having 1 to 600 carbon atoms and may contain an aromatic ring, an alicyclic group, an ether group or an ester group).