hydrocarbon group which may have a substituent and a divalent linking group having hetero atoms. 

[0076] As W, a group represented by Chemical Formula: CH 2 =C(R)-Yaxo_ is suitably exemplified. In this chemical formula, R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms, and Yaxo represents a single bond or a divalent linking group. 

[0077] In the chemical formula shown above, as the alkyl group having 1 to 5 carbon atoms as R, a linear or branched alkyl group having 1 to 5 carbon atoms is preferable, and specific examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. The halogenated alkyl group having 1 to 5 carbon atoms is a group in which some or all hydrogen atoms of the above-described alkyl group having 1 to 5 carbon atoms have been substituted with halogen atoms. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable. As R, a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a fluorinated alkyl group having 1 to 5 carbon atoms is preferable, a hydrogen atom or a methyl group is more preferable, and a methyl group is particularly prefer› able in terms of industrial availability. 

[0078] In the chemical formula shown above, the divalent linking group as Yaxo is not particularly limited, and suitable examples thereof include a divalent hydrocarbon group which may have a substituent and a divalent linking group having hetero atoms. 

[0079] Divalent Hydrocarbon Group which May have Substituent: 

[0080] In a case where Yaxo represents a divalent hydro› carbon group which may have a substituent, the hydrocar› bon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. 0 

[0081] Aliphatic Hydrocarbon Group as Yax 

[0082] The aliphatic hydrocarbon group indicates a hydro› carbon group that has no aromaticity. The aliphatic hydro› carbon group may be saturated or unsaturated. In general, the aliphatic hydrocarbon group is preferably saturated. 

[0083] Examples of the aliphatic hydrocarbon group include a linear or branched aliphatic hydrocarbon group, and an aliphatic hydrocarbon group containing a ring in the structure thereof. 

[0084] Linear or Branched Aliphatic Hydrocarbon Group 

[0085] The linear aliphatic hydrocarbon group has prefer› ably 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, still more preferably 1 to 4 carbon atoms, and most preferably 1 to 3 carbon atoms. 

[0086] As the linear aliphatic hydrocarbon group, a linear alkylene group is preferable. Specific examples thereof include a methylene group [-CH 2 -], an ethylene group [-(CH 2 ) 2 -], a trimethylene group [-(CH 2 )$_{3}$ -], a tetram› ethylene group [-(CH 2 )$_{4}$ -] and a pentamethylene group [-(CH2)s-l- 

[0087] The branched aliphatic hydrocarbon group has preferably 2 to 10 carbon atoms, more preferably 3 to 6 carbon atoms, still more preferably 3 or 4 carbon atoms, and most preferably 3 carbon atoms. 

[0088] As the branched aliphatic hydrocarbon group, a branched alkylene group is preferred, and specific examples thereof include alkylalkylene groups, for example, alkylm- 

ethylene groups such as ----CH(CH$_{3}$)-, ----CH(CH 2 CH$_{3}$)-, ----C(CH$_{3}$ ) 2 -, -C(CH$_{3}$)(CH 2 CH$_{3}$)-, -C(CH$_{3}$ ) (CH 2 CH 2 CH$_{3}$)-, and -C(CH 2 CH$_{3}$ ) 2 -; alkylethylene groups such as ----CH(CH$_{3}$)CH 2 -, ----CH(CH$_{3}$)CH(CH$_{3}$)-, ----C(CH$_{3}$ ) 2 CH 2 -, -CH(CH 2 CH$_{3}$)CH 2 -, and ----C(CH 2 CH$_{3}$ ) 2 ----CH 2 -; alkyltrimethylene groups such as ----CH(CH$_{3}$)CH 2 CH 2 -, and ----CH 2 CH(CH$_{3}$)CH 2 -; and alkyltetramethylene groups such as -CH(CH$_{3}$ ) CH 2 CH 2 CH 2 -, and ----CH 2 CH(CH$_{3}$)CH 2 CH 2 -. As the alkyl group in the alkylalkylene group, a linear alkyl group having 1 to 5 carbon atoms is preferable. 

[0089] The linear or branched aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms which has been substituted with a fluorine atom, and a carbonyl group. 

[0090] Aliphatic Hydrocarbon Group Containing Ring in Structure Thereof 

[0091] Examples of the aliphatic hydrocarbon group con› taining a ring in the structure thereof include a cyclic aliphatic hydrocarbon group which may have a substituent containing a hetero atom in the ring structure thereof (a group in which two hydrogen atoms have been removed from an aliphatic hydrocarbon ring), a group in which the cyclic aliphatic hydrocarbon group is bonded to the terminal of a linear or branched aliphatic hydrocarbon group, and a group in which the cyclic aliphatic hydrocarbon group is interposed in a linear or branched aliphatic hydrocarbon group. As the linear or branched aliphatic hydrocarbon group, the same groups as those described above can be used. 

[0092] The cyclic aliphatic hydrocarbon group has pref› erably 3 to 20 carbon atoms and more preferably 3 to 12 carbon atoms. 

[0093] The cyclic aliphatic hydrocarbon group may be a polycyclic group or a monocyclic group. As the monocyclic alicyclic hydrocarbon group, a group in which 2 hydrogen atoms have been removed from a monocycloalkane is pref› erable. The monocycloalkane has preferably 3 to 6 carbon atoms, and specific examples thereof include cyclopentane and cyclohexane. As the polycyclic alicyclic hydrocarbon group, a group in which two hydrogen atoms have been removed from a polycycloalkane is preferable. As the poly› cycloalkane, a group having 7 to 12 carbon atoms is pref› erable. Examples of the polycycloalkane include adaman› tane, norbomane, isobornane, tricyclodecane, and tetracyclododecane. 

[0094] The cyclic aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, and a carbonyl group. 

[0095] The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and a methyl group, an ethyl group, a propyl group, an n-butyl group or a tert-butyl group is particularly preferable. 

[0096] The alkoxy group as the substituent is preferably an alkoxy group having 1 to 5 carbon atoms, more preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group or a tert-butoxy group, and most preferably a methoxy group or an ethoxy group. 

