Lubrication method with alkoxylated perfluoropolyether

Abstract

A lubrication method comprising applying to a surface to be lubricated a polymer comprising a partially or fully fluorinated, straight or branched, polyoxyalkylene chain (chain R f ) having two chain ends, wherein one or both chain end(s) bear(s) a hydroxy- or alkoxy-terminated polyoxyalkylene chain free from fluorine atoms (chain R a ), said chain comprising from 4 to 50 fluorine-free oxyalkylene units, said units being the same or different from one another and being selected from —CH 2 CH 2 O— and —CH 2 CH(J)O—, wherein J is independently straight or branched alkyl or aryl, with the proviso that, if both chain ends bear a hydroxy-terminated chain Ra comprising only —CH 2 CH 2 O— units, chain Rf does not consist only of —CF 2 CF 2 O-units. Lubricant compositions containing the polymer and methods for preparing the polymer are also herein disclosed.

1 . A lubrication method comprising applying to a surface to be lubricated a polymer complying with formula (I) below:
   A-O—R f —(CF 2 ) x —CFZ—CH 2 —O—R a   (I)
   wherein:
 R f  is a (per)fluoropolyoxyalkylene chain having an average number molecular weight M n  ranging from 100 to 8,000, and comprising repeating units, which may be equal to or different from one another, selected from: 
   (i) —CFXO—, wherein X is F or CF 3 ,   (ii) —CFXCFXO—, wherein X, equal or different at each occurrence, is F or CF 3 , with the proviso that at least one of X is —F,   (iii) —CF 2 CF 2 CW 2 O—, wherein each of W, equal or different from each other, are F or H,   (iv) —CF 2 CF 2 CF 2 CF 2 O—,   (v) —(CF 2 ) j —CFZ′—O— wherein j is an integer from 0 to 3 and Z′ is general —OR f ′T, wherein R f ′ is a fluoropolyoxyalkene chain comprising a number of repeating units from 0 to 10, said repeating units being selected from: CFXO—, —CF 2 CFXO—, —CF 2 CF 2 CF 2 O—, —CF 2 CF 2 CF 2 CF 2 O—, with each of each of X being independently F or CF 3  and T being a C 1 -C 3  perfluoroalkyl group;
 Z is fluorine or CF 3 ; 
 x is 0 or 1, with the proviso that, when, x is 1, Z is F; 
 A is —(CF 2 ) x —CFZ—CH 2 —O—R a , wherein x and Z are as defined above, or is a straight or branched C 1 -C 4  perfluoroalkyl group wherein one fluorine atom can be substituted by one chlorine atom or one hydrogen atom, with the proviso that, if chlorine is present in group A, it is in a molar amount lower than 2% with respect to the overall amount of end groups and 
 R a  is a hydroxy-, alkoxy- or acyloxy-terminated polyoxyalkylene chain free from fluorine atoms (chain R a ), said chain comprising from 4 to 50 fluorine-free oxyalkylene units, said units being the same or different from one another and being selected from —CH 2 CH 2 O—, —CH 2 CH(CH 3 )O—, —CH 2 CH(CH 2 CH 3 )O— and —CH 2 CH(Ph)O—, with the proviso that, if A is —(CF 2 ) x —CFZ—CH 2 —R a  and chain R a  is hydroxy-terminated and comprises only —CH 2 CH 2 O— units, chain R f  does not consist only of —CF 2 CF 2 O— repeating units. 
   
     
     
         2 . The method according to  claim 1 , wherein chain R f  in polymer (I) is selected from formulae (a)-(c) below:
   —(CF 2 O) n (CF 2 CF 2 O) m (CF 2 CF 2 CF 2 O) p (CF 2 CF 2 CF 2 CF 2 O) q —  (a)
   wherein m, n, p, q are 0 or integers selected in such a way as chain R f  meets the above number average molecular weight requirement, with the proviso that if, p and q are simultaneously 0, n is not 0;
   —(CF 2 CF(CF 3 )O) a (CF 2 CF 2 O) b (CF 2 O) c (CF(CF 3 )O) d —  (b)
 
   wherein a, b, c, d are 0 or integers selected in such a way as chain R f  meets the above number average molecular weight requirement; with the proviso that, at least one of a, c and d is not 0;
   —(CF 2 CF(CF 3 )O) e (CF 2 O) f (CF(CF 3 )O) g —  (c)
 
   wherein e, f, g are 0 or integers selected in such a way as chain R f  meets the above number average molecular weight requirement.   
     
     
         3 . The method according to  claim 1 , wherein chain R a  in polymer (I) complies with formula (R a -I) below:
   —(CH 2 CH 2 O) r (CH 2 CH(CH 3 )O) s (CH 2 CH(CH 2 CH 3 )O) t (CH 2 CH(Ph)O) u R 1   (R a -I)
   wherein r, s, t and u are independently selected from 0 and a positive number, with r+s+t+u ranging from 4 to 50, and R 1  is selected from hydrogen, C 1 -C 4  straight or branched alkyl, and —C(O)R 2 , wherein R 2  is C 1 -C 4  straight or branched (halo)alkyl, with the proviso that, if chain R f  of compounds (I) comprises only —CF 2 CF 2 O— units and bears at both ends a chain (R a -I) wherein s, t and u are 0, R 1  is not hydrogen.   
     
     
         4 . The method according to  claim 3 , wherein in chain (R a -I), r is a positive number ranging from 4 to 15, s, t and u are 0 and R 1  is selected from hydrogen or methyl, with the proviso that, if chain R f  of compounds (I) comprises only —CF 2 CF 2 O— units and bears at both ends a chain (R a -I), R 1  is not hydrogen. 
     
     
         5 . The method according to  claim 3 , wherein, in chain (R a -I), r, t and u are 0, s is a positive number ranging from 4 to 15 and R 1  is selected from hydrogen or methyl. 
     
     
         6 . The method according to  claim 3 , wherein in chain (R a -I), t and u are 0, r+s ranges from 4 to 15 and R 1  is selected from hydrogen or methyl. 
     
     
         7 . The method according to  claim 1 , wherein polymer (I) complies with formula (I-A) below:
   R a —O—CH 2 —CF 2 —O—R f —CF 2 —CH 2 —O—R a   (I-A)
   wherein R a  is a hydroxy-, alkoxy- or acyloxy-terminated polyoxyalkylene chain free from fluorine atoms (chain R a ), said chain comprising from 4 to 50 fluorine-free oxyalkylene units, said units being the same or different from one another and being selected from —CH 2 CH 2 O—, —CH 2 CH(CH 3 )O—, —CH 2 CH(CH 2 CH 3 )O— and —CH 2 CH(Ph)O—, and R f  complies with formula (a):
   —(CF 2 O) n (CF 2 CF 2 O) m (CF 2 CF 2 CF 2 O) n (CF 2 CF 2 CF 2 CF 2 O) q —  (a)
 
   wherein m, n, p, q are 0 or integers selected in such a way as chain R f  meets the number average molecular weight requirement, with the proviso that if, p and q are simultaneously 0, n is not 0.   
     
     
         8 . A polymer complying with formula (I*)
   A-O—R f —(CF 2 ) x —CFZ—CH 2 —O—R a   (I*)
   wherein:
 R f  is a (per)fluoropolyoxyalkylene chain having an average number molecular weight M n  ranging from 100 to 8,000, and comprising repeating units, which may be equal to or different from one another, selected from 
   (i) —CFXO—, wherein X is F or CF 3 ,   (ii) —CFXCFXO—, wherein X, equal or different at each occurrence, is F or CF 3 , with the proviso that at least one of X is —F,   (iii) —CF 2 CF 2 CW 2 O—, wherein each of W, equal or different from each other, are F or H,   (iv) —CF 2 CF 2 CF 2 CF 2 O—,   (v) —(CF 2 ) j —CFZ′—O— wherein j is an integer from 0 to 3 and Z′ is —OR f ′T, wherein R f ′ is a fluoropolyoxyalkene chain comprising a number of repeating units from 0 to 10, said repeating units being selected from: CFXO—, —CF 2 CFXO—, —CF 2 CF 2 CF 2 O—, —CF 2 CF 2 CF 2 CF 2 O—, with each of each of X being independently F or CF 3 , and T being a C 1 -C 3  perfluoroalkyl group;
 Z is fluorine or CF 3 ; 
 x is 0 or 1, with the proviso that, when, x is 1, Z is F; 
 A is (CF 2 ) x —CFZ—CH 2 —O—R a , wherein x and Z are as defined above, or is selected from straight or branched C 1 -C 4  perfluoroalkyl groups wherein one fluorine atom can be substituted by one chlorine atom or one hydrogen atom, with the proviso that, if chlorine is present in group A, it is in a molar amount lower than 2% with respect to the overall amount of end groups and 
 R a  complies with formula (R a -I*) below:
   —(CH 2 CH 2 O) r (CH 2 CH(CH 3 )O) s (CH 2 CH(CH 2 CH 3 )O) t (CH 2 CH(Ph)O) u R 1   (R a -I*)
 
 
   wherein:
 r, s, t and u are independently selected from 0 and a positive number and r+s+t+u is a positive number ranging from 4 to 50; 
   and R 1  is selected from hydrogen, C 1 -C 4  straight or branched alkyl, and —C(O)R 2 , wherein R 2  is C 1 -C 4  straight or branched (halo)alkyl, with the proviso that, when R 1  is hydrogen, at least one of s, t and u is not 0.   
     
     
         9 . The polymer according to  claim 8  wherein chain R f  is selected from formulae (a*)-(c*) here below:
   —(CF 2 O) n (CF 2 CF 2 O) m CF 2 CF 2 CF 2 O) p (CF 2 CF 2 CF 2 CF 2 O) q —  (a*)
 
 wherein m, n, p, q are 0 or integers selected in such a way as chain R f  meets the above number average molecular weight requirement;
   —(CF 2 CF(CF 3 )O) a (CF 2 CF 2 O) b (CF 2 O) c (CF(CF 3 )O) d —  (b*)
 
 
 wherein a, b, c, d are 0 or integers selected in such a way as chain R f  meets the above number average molecular weight requirement; with the proviso that, at least one of a, c and d is not 0;
   —(CF 2 CF(CF 3 )O) e (CF 2 O) f (CF(CF 3 )O) g —  (c*)
 
 
 wherein e, f, g are 0 or integers selected in such a way as chain R f  meets the above number average molecular weight requirement. 
 
     
     
         10 . The polymer according to  claim 8 , which is a polymer of formula (I*-A) below
   R a —O—CH 2 —CF 2 —O—R f —CF 2 —CH 2 —O—R a   (I*-A)
   wherein:
 R a  complies with formula (R a -I*) below:
   —(CH 2 CH 2 O) r (CH 2 CH(CH 3 )O) s (CH 2 CH(CH 2 CH 3 )O) t (CH 2 CH(Ph)O) u R 1   (R a -I*)
 
 wherein:
 r, s, t and u are independently selected from 0 and a positive number and r+s+t+u is a positive number ranging from 4 to 50; 
 
 and R 1  is selected from hydrogen, C 1 -C 4  straight or branched alkyl, and —C(O)R 2 , wherein R 2  is C 1 -C 4  straight or branched (halo)alkyl, with the proviso that, when R 1  is hydrogen, at least one of s, t and u is not 0 and 
 
 R f  complies with formula (a*):
   —(CF 2 O) n (CF 2 CF 2 O) m (CF 2 CF 2 O) p (CF 2 CF 2 CF 2 CF 2 O) q —  (a*)
 
 
   wherein m, n, p, q are 0 or integers selected in such a way as chain R f  meets the number average molecular weight requirement.   
     
     
         11 . The polymer according to  claim 10  wherein r, t and u in formula (R a -I*) are 0 and s is a positive number ranging from 4 to 15. 
     
     
         12 . The polymer according to  claim 10  wherein in formula (R a -I*) r+s is a positive number ranging from 4 to 15 and t and u are 0. 
     
     
         13 . A composition comprising:
 (a) a polymer as defined in  claim 8 ; in admixture with one or more of   (b) a lubricant base oil;   (c) a thickening agent;   (d) an additive; and optionally   (e) a solvent.   
     
     
         14 . The method according to  claim 1 , wherein R f  is a (per)fluoropolyoxyalkylene chain having an average number molecular weight M n  ranging from 800 to 3,000. 
     
     
         15 . The method according to  claim 1 , wherein R f  consists of repeating units, which may be equal to or different from one another, selected from:
 (i) —CFXO—, wherein X is F or CF 3 ,   (ii) —CFXCFXO—, wherein X, equal or different at each occurrence, is F or CF 3 , with the proviso that at least one of X is —F,   (iii) —CF 2 CF 2 CW 2 O—, wherein each of W, equal or different from each other, are F or H,   (iv) —CF 2 CF 2 CF 2 CF 2 O—,   (v) —(CF 2 ) j —CFZ′—O— wherein j is an integer from 0 to 3 and Z′ is —OR f ′T, wherein R f ′ is a fluoropolyoxyalkene chain comprising a number of repeating units from 0 to 10, said repeating units being selected from: —CFXO—, —CF 2 CFXO—, —CF 2 CF 2 CF 2 O—, —CF 2 CF 2 CF 2 CF 2 O—, with each of each of X being independently F or CF 3  and T being a C 1 -C 3  perfluoroalkyl group.   
     
     
         16 . The method according to  claim 2 , wherein
 the m/n ratio is between 0.1 and 20 when m is other than 0;   (p+q)/(m+n) is between 0 and 0.2 when (m+n) is other than 0;   a/b is between 0.1 and 10 when b is other than 0;   (c+d)/(a+b) is between 0.01 and 0.5 when (a+b) is other than 0; and   (f+g)/e is between 0.01 and 0.5 when e is other than 0   
     
     
         17 . The polymer according to  claim 8 , wherein R f  is a (per)fluoropolyoxyalkylene chain having an average number molecular weight M n  ranging from 800 to 3,000. 
     
     
         18 . The polymer according to  claim 8 , wherein R f  consists of repeating units, which may be equal to or different from one another, selected from:
 (i) —CFXO—, wherein X is F or CF 3 ,   (ii) —CFXCFXO—, wherein X, equal or different at each occurrence, is F or CF 3 , with the proviso that at least one of X is —F,   (iii) —CF 2 CF 2 CW 2 O—, wherein each of W, equal or different from each other, are F or H,   (iv) —CF 2 CF 2 CF 2 CF 2 O—,   (v) —(CF 2 ) j —CFZ′—O— wherein j is an integer from 0 to 3 and Z′ is —OR f ′T, wherein R f ′ is a fluoropolyoxyalkene chain comprising a number of repeating units from 0 to 10, said repeating units being selected from: —CFXO—, —CF 2 CFXO—, —CF 2 CF 2 CF 2 O—, —CF 2 CF 2 CF 2 CF 2 O—, with each of each of X being independently F or CF 3  and T being a C 1 -C 3  perfluoroalkyl group.   
     
     
         19 . The polymer according to  claim 9 , wherein
 the m/n ratio is between 0.1 and 20 when m is other than 0;   (p+q)/(m+n) is between 0 and 0.2 when (m+n) is other than 0;   a/b is between 0.1 and 10 when b is other than 0;   (c+d)/(a+b) is between 0.01 and 0.5 when (a+b) is other than 0; and   (f+g)/e is between 0.01 and 0.5 when e is other than 0.