content_image/942225.jpg content_image/942223.jpg content_image/942222.jpg content_image/942226.jpg content_image/942224.jpg content_image/942221.jpg
in which M3- l is a structural unit represented by the formula (53): 

<img src='content_image/942225.jpg'>

wherein Rf5° and Rf’ $^{1 }$are the same or different and each is a 15 perfluoroalkyl group having 1 to 20 carbon atoms; X$^{10 }$and X $^{11 }$are the same or different and each is H, F, an alkyl group having 1 to 20 carbon atoms or a fluorine-containing alkyl group which has 1 to 20 carbon atoms and may have ether 20 bond; X$^{12 }$is hydrogen atom, fluorine atom, an alkyl group having 1 to 20 carbon atoms, a fluorine-containing alkyl group which has 1 to 20 carbon atoms and may have ether bond, OH group or a group represented by the formula: 25 

<img src='content_image/942223.jpg'>

wherein Rf5 $^{2 }$and Rf5 $^{3 }$are the same or different and each is a perfluoroalkyl group having 1 to 20 carbon atoms; R$^{50 }$is at least one selected from an alky lene group or fluorine-contain› ing alkylene group which has 1 to 3 carbon atoms and con› stitutes a ring; R$^{51 }$and R$^{52 }$are the same or different and each is at least one selected from a divalent hydrocarbon group which has 1 to 7 carbon atoms and constitutes a ring, oxygen atom, a divalent hydrocarbon group having ether bond which has the sum of oxygen atoms and carbon atoms of 2 to 7 and constitutes a ring, a divalent fluorine-containing alkylene group which has 1 to 7 carbon atoms and constitutes a ring or a divalent fluorine-containing alkylene group having ether bond which has the sum of oxygen atoms and carbon atoms of 2 to 7 and constitutes a ring; the sum of carbon atoms consti› tuting a trunk chain inR$^{51 }$and R$^{52 }$is not more than 7, and OH group or a group represented by the formula: 

<img src='content_image/942222.jpg'>

wherein Rf5 $^{2 }$and Rf5$^{3 }$are as defined above, may be bonded to any of carbon atoms in R 51 ; R $^{53 }$and R$^{54 }$are the same or different and each is a divalent alkylene group having 1 or 2 carbon atoms or a divalent fluorine-containing alky lene group having 1 or 2 carbon atoms; n50, n51, n52, n53 and n54 are the same or different and each is 0 or 1, 

N3-l is a structural unit derived from a monomer copolymer› izable with the monomer to introduce the structural unit M3-l, and 

the structural units M3-l and N3-l are contained in amounts of from 0.1 to 100% by mole and from Oto 99.9% by mole, respectively. 

(53) 

The ninth of the present invention relates to a fluorine› containing polymer having a number average molecular weight of from 500 to 1,000,000 which is represented by the formula (61): 

<img src='content_image/942226.jpg'>

in which M3-l is a structural unit represented by the formula (54): 

<img src='content_image/942224.jpg'>

wherein Rf5° is a perfluoroalkyl group having 1 to 20 carbon atoms; X $^{10 }$and X $^{11 }$are the same or different and each is H, F, an alkyl group having 1 to 20 carbon atoms or a fluorine› containing alkyl group which has 1 to 20 carbon atoms and may have ether bond; R$^{50 }$is at least one selected from an alkylene group or fluorine-containing alkylene group which has 1 to 3 carbon atoms and constitutes a ring; R$^{51 }$and R$^{52 }$are the same or different and each is at least one selected from a divalent hydrocarbon group which has 1 to 7 carbon atoms and constitutes a ring, oxygen atom, a divalent hydrocarbon group having ether bond which has the sum of oxygen atoms and carbon atoms of 2 to 7 and constitutes a ring, a divalent fluorine-containing alkylene group which has 1 to 7 carbon atoms and constitutes a ring or a divalent fluorine-containing alkylene group having ether bond which has the sum of oxy- gen atoms and carbon atoms of 2 to 7 and constitutes a ring; the sum of carbon atoms constituting a trunk chain in R$^{51 }$and R$^{52 }$is not more than 7, and OH group or a group represented by the formula: 

<img src='content_image/942221.jpg'>

wherein Rf5 $^{2 }$and Rf5 $^{3 }$are the same or different and each is a perfluoroalkyl group having 1 to 20 carbon atoms, may be bonded to any of carbon atoms in R 51 ; R $^{53 }$and R$^{54 }$are the same or different and each is a divalent alkylene group having 1 or 2 carbon atoms or a divalent fluorine-containing alky lene group having 1 or 2 carbon atoms; n50, n51, n52, n53 and n54 are the same or different and each is 0 or 1, 

(54) 

