| abstract |
(B1), (B2), (C1) and (C2): wherein at least one of the symbols is as defined in the description, Of the perfluoro (poly) ether group-containing silane compound represented by the above general formula, and a perfluoro (poly) ether group having a molecular weight of 3,000 or less among the perfluoro (poly) ether group- Containing silane compound is not more than 9 mol%. |