Fluorinated lubricants

Abstract

Fluorinated lubricants comprising “pour point depressant” additives of structure: X 1 —O(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 —X 2   (I) wherein X 1 , X 2 , have formula —(CF 2 ) z CF 3 wherein z is an integer from 0 to 3; n is an integer between 1 and 200; m is an integer between 0 and 200; p, q are integers between 0 and 10; (p+q)/(p+q+m+n)≦0.05; m/n≦0.7; the number average molecular weight of (I) is between 1,000 and 10,000.

1 . Use as “pour point depressant” additives for fluorinated oils, of compounds having the following structure: 
       X 1 —O(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 —X 2   (I) 
     wherein: 
 the repeating units —CF 2 O—, —CF 2 CF 2 O—, —CF 2 CF 2 CF 2 O—, —CF 2 CF 2 CF 2 CF 2 O—, are statistically distributed along the chain;  
 —X 1  and —X 2  are perfluoroalkyl chain end groups equal to or different from each other, having formula —(CF 2 ) z CF 3  wherein z is an integer from 0 to 3;  
 n is an integer from 1 to 200,  
 m is an integer from 0 to 200,  
 p, q are integers from 0 to 10, preferably from 0 to 5, more preferably from 0 to 1, still more preferably 0,  
 with the proviso that:  
 the ratio (p+q)/(p+q+m+n) is lower than or equal to 0.05, being also equal to 0, (p+q+m+n) being different from 0;  
 the ratio m/n, when n is different from 0, is lower than or equal to 0.7, preferably lower than 0.5, more preferably lower than 0.35;  
 the number average molecular weight of the compounds 
 (I) ranges from 1,000 to 10,000, preferably from 2,000 to 8,000, more preferably from 2,400 to 5,000; the chlorine atoms in the compounds of formula (I) determined by  19 F NMR analysis are substantially absent.  
 
 
   
   
       2 . Use according to  claim 1 , wherein the fluorinated oils are perfluoropolyether oils having viscosity at 20° C. between 10 and 4,000 cSt, preferably between 30 and 2,000 cSt, and containing one or more of the following repeating units: —CFXO— wherein X is equal to F or CF 3 ; —CF 2 CF 2 O—, —(C 3 F 6 O)—, —CF 2 CF 2 CF 2 O—, —CF 2 CF 2 CF 2 CF 2 O—, said units being statisticall distributed along the backbone.  
   
   
       3 . Use according to  claim 2 , wherein the perfluoropolyether oils are selected from the following classes: 
       E—O—(CF 2 CF(CF 3 )O) m′ (CFXO) n′ —E′  (1) wherein:    X is equal to F or CF 3 ;    E and E′, equal to or different from each other, are selected from CF 3 , C 2 F 5  or C 3 F 7 , one fluorine atom of one or both the end groups being replaceable with Cl and/or H; m′ and n′ are integers such that the ratio m′/n′ is between 20 and 1,000, n′ being different from zero; the units being statistically distributed along the backbone, the viscosity of the product being within the above range;     C 3 F 7 O(CF(CF 3 )CF 2 O) o,  —D  (2)   wherein:    D is equal to —C 2 F 5  or —C 3 F 7 , one fluorine atom of one or both the end groups being replaceable with Cl and/or H; o′ is an integer such that the viscosity of the product is within the above range;     {C 3 , F 7 0—(CF(CF 3 )CF 2 O) p′ —CF(CF 3 )—} 2   (3)   wherein:    p′ is an integer such that the viscosity of the compound is within the above range, one F atom of one or both the end groups C 3 F 7  being replaceable with Cl and/or H;     E—O—(CF 2 CF(CF 3 )O ) q′ (C 2 F 4 O) r′ (CFX) s′ —E′  (4)   wherein:    X is equal to F or CF 3 ;    E and E′, equal to or different from each other, are as above; q′, r′ and s′ are integers including 0, and such that the viscosity of the product is within the above range;      E—O—(C 2 F 4 O) t′ (CF 2 O) u′ —E′  (5)   wherein:    E and E′, equal to or different from each other, are as above; t′ and u′ are integers such that the ratio    t′/u′ is between 0.1 and 5, u′ being different from 0 and the viscosity of the product is within the above range;     E—O—(CF 2 CF 2 CF 2 O) v′ —E′  (6)   wherein:    E and E′, equal to or different from each other, are as above; v′ is a number such that the viscosity of the product is within the above range;     D—O—(CF 2 CF 2 O) z′— D′  (7)   wherein:    D and D′, equal to or different from each other, are selected from C 2 F 5  or C 3 F 7 , one fluorine atom of one or both the end groups being replaceable with Cl and/or H; z′ is an integer such that the viscosity of the product is within the above range     E 1 —O(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 —E 2   (8)   wherein:    E 1  and E 2  are perfluoroalkyl end groups equal to or different from each other, having formula —(CF 2 ) z CF 3  wherein z is an integer from 0 to 3; n, m, p, q are integers equal to or different from each other comprised between 0 and 100 and selected so that the viscosity of the oil is within the above range and such that the ratio m/n is between 2 and 20, n being different from 0; (p+q)/(n+m+p+q) is between 0.05 and 0.2, (n+m+p+q) being different from 0; n/(n+m+p+q) is between 0.05 and 0.40, (n+m+p+q) being different from 0.    
   
   
       4 . Use according to  claim 3 , wherein the perfluoropolyether oils are those of the classes (1), (4), (5), (8) or their mixtures and those of the class (2) and (6).  
   
   
       5 . Use according to  claim 1 , wherein the pour point depressant additives are used in amounts ranging from 0.1% to 30% by weight with respect to the final composition, preferably from 1% to 20%, more preferably from 5% to 10%.  
   
   
       6 . Use according to  claim 1 , wherein mixtures of additives of general formula (I) and mixtures of perfluoropolyether oils are used.  
   
   
       7 . Lubricating compositions comprising from: 
 A) 70% to 99.9% by weight of at least a fluorinated oil, preferably a perfluoropolyether oil having viscosity at 20° C. between 10 and 4,000 cSt, preferably between 30 and 2,000 cSt, and comprising one or more of the following repeating units: —CFXO— wherein X is equal to F or CF 3 ; —CF 2 CF 2 O—, —(C 3 F 6 O—, —CF 2 CF 2 CF 2 O—, —CF 2 CF 2 CF 2 CF 2 O—, said units being statistically distributed along the backbone; and    B) 0.1% to 30% by weight of at least an additive of formula (I).    
   
   
       8 . Compositions according to  claim 3  comprising at least an additive of formula (I) and at least an oil of the classes (1), (5); preferably an oil of class (5) having a viscosity between 30 cSt and 300 cSt.  
   
   
       9 . Lubricating compositions according to  claim 7  comprising antirust, antiwear, antioxidant additives, suitable thermal stabilizers for perfluoropolyether oils.  
   
   
       10 . Use of the compounds (I) of  claim 1  as lubricating oils having a low pour point.  
   
   
       11 . Perfluoropolyether lubricating oils of  claim 10.