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nylthioxy group or a p-tolylthioxy group; an alkoxycarbonyl group such as a methoxycarbonyl group or a butoxycarbonyl group; an aryloxycarbonyl group such as a phenoxycarbonyl group; an acetoxy group; a linear or branched alkyl group such as a methy 1 group, an ethy 1 group, a propy 1 group, a buty 1 group, a heptyl group, a hexyl group, a dodecyl group or a 2-ethylhexyl group; a cycloalkyl group such as a cyclohexyl group; an alkenyl group such as a vinyl group, a propenyl group or a hexenyl group; an alkynyl group such as an acety› lene group, a propynyl group or a hexynyl group; an aryl group such as a phenyl group or a tolyl group; a hydroxyl group; a carboxyl group; a sulfonate group; a carbonyl group; and the like. Of these, a linear or branched alkyl group is preferred from the viewpoint of the simultaneous attainment of roughness improvement and sensitivity enhancement. 

Specific examples of the groups having these cycloaliphatic groups or noncyclic hydrocarbon groups will be shown below. In the formulae, * represents a site of con- nection to A (when A is a single bond, Ar). 

<img src='content_image/888040.jpg'>

<img src='content_image/888041.jpg'>

Of these, the following structures are preferred. 

<img src='content_image/888042.jpg'>

