103  US 9,423,690 B2  104  The polar group which may be possessed by the repeating  unit having a polar group may be a carbonate group such as  a cyclic carbonate ester structure, and the resin (A) prefer› ably contain a repeating unit having a cyclic carbonate ester  structure.  The repeating unit having a cyclic carbonate ester struc› ture is preferably the repeating unit represented by Formula  (A-1).  In Formula (A-1 ),  RA  $^{1 }$represents a hydrogen atom or an  alkyl group.  If n is 2 or more,  RA  $^{2}$’s each independently represents a  substituent.  A represents a single bond or a divalent linking group.  Z represents a atomic group forming a monocyclid or  polycyclic structure together with a group represented by  -O----C(=O)-O- in the formula.  n represents an integer of 0 or more.  Formula (A-1) will be described in detail.  The alkyl group represented by  RA  $^{1 }$may have a substitu› ent such as a fluorine atom.  RA  1  represents preferably a  hydrogen atom, a methyl group or a trifluormethyl group,  and more preferably a methyl group.  The substituent represented by  RA  2  is, for example, an  alkyl group, a cycloalkyl group, a hydroxyl group, an alkoxy  group, an amino group and an alkoxycarbonylamino group.  The substituent is preferably an alkyl group having 1 to 5  carbon atoms, for example, a straight alkyl group having 1  to 5 carbon atoms such as a methyl group, an ethyl group,  a propyl group and a butyl group; and a branched alkyl  group having 3 to 5 carbon atoms such as an isopropyl  group, an isobutyl group and at-butyl group. An alkyl group  may have a substituent such as a hydroxyl group.  n represents the number of substituents, and is an integer  of 0 or more. For example, n is preferably Oto 4, and more  preferably 0.  Examples of the a divalent linking group represented by 65  A may include an alkylene group, a cycloalkylene group, an  ester bond, an amide bond, an ether bond, an urethane bond,  an urea bond, or combination thereof. Examples of the  alkylene group may include preferably an alkylene group  having 1 to 10 carbon atoms, more preferably an alkylene  group having 1 to 5 carbon atoms, and for example a  methylene group, an ethylene group, an propylene group,  and the like.  In one aspect of the present invention, A is preferably a  single bond, or an alkylene group.  The moncyclic group containing ---O-C(=O)---0-,  represented by Z is, for example, a 5- to 7-membered ring in  which nA=2 to 4 in the cyclic carbonate ester represented by  the following Formula (a), and preferably a 5-membered  ring or a 6-membered ring (nA=2 or 3), and more preferably  a 5-membered ring (nA=2).  The polycyclic group containing -O----C(=O)-O› represented by Z may, for example, be a structure in which  a cyclic carbonate ester represented by the following For- mula (a) are bound with 1 or 2 or more other ring structure  to form a condensed ring or to form a spiro ring. "Other ring  structures" capable of forming a condensed ring or spiro ring  may be an alicyclid hydrocarbon group, an aromatic hydro› carbon group or a heterocyclic ring.  The monomer corresponding to the repeating unit repre› sented by Formula (A-1) may be synthesized by a conven› tionally known method described in, for example, Tetrahe› dron Letters, Vol. 27, No. 32 p. 3741(1986), Organic Letters,  Vol. 4, No. 15 p. 2561(2002), and the like.  In the resin (A), the repeating unit represented by Formula  (A-1) may be contained either alone or in a combination of  two or more thereof.  Hereinafter, specific examples of the repeating unit hav› ing a cyclic carbonate ester structure are shown below, but  the present invention is not limited thereto.  In addition,  RA  $^{1 }$in the following specific examples has the  same meaning as RA 1  in Formula (A-1).  Rx  ~  (A-1) 25  30  (a)  -continued 