MXPA97005146A - Procedure of polymerization in suspens - Google Patents

Abstract

Use of surfactants in the suspension polymerization of fluorinated monomers to prepare fluoropolymers containing hydrogen, said surfactants having the general formula: Rf- [L- (OCHR1-CHR2) m-OZ)] i, wherein: i is equal a 1ó2; m is an integer between 4 and 60; L can be selected from. - (CFY-CO-O) pR'- and - (CFY-CO-NH) pR'-, where p is an integer equal to 0a1, Y = F, CF3; R '= a C1 alkyl radical; -C5, linear or branched when possible, R1, R2 can be both H or the first H and the last CH3, Z can be H, C1-C3 alkyl radical, linear or branched when possible, or (CH2) nOH being n an integer from 1 to 6, Rf is a perfluoroalkyl radical or a perfluoropolyether radical, having a number average molecular weight of between 250 and 15;

Description

PROCEDURE OF POLYMERIZATION IN SUSPENSION DESCRIPTIVE MEMORY OF THE INVENTION The present invention relates to a process of (co) polymerization in suspension to prepare thermoplastic fluoropolymers containing hydrogen. Various classes of fluorinated polymers containing hydrogen and having thermoplastic properties are known in the art. A first class consists of copolymers of perhalogenofluoroolefins with non-halogenated olefins, such as, for example, copolymers with ethylene tet afluoroelene (TFE) or chlorotropfluoroethylene (C7FE), optionally containing a third fluorinated coronomer in amounts comprised in + and 0.1 and 10% in rnoles (see for example U.S. Patent 3,524,250). The preparation of such copolymers is generally carried out in suspension and, especially in the case of ethylene CTFE copolymers, is preferably carried out at room temperature. Another class of fluoropolymers containing hydrogen consists of polyvinylidene fluoride (PVDF) and modified PVDF with small amounts (0.1-10 mole%) of other fluorinated comonomers. The use of suspending and / or wetting agents (both here indicated generically as "wetting agents") in the suspension polymerization, especially in the "opolization of the VDF, is known, see eg Encyclopedia of Polyrner Science and Engmeermg p. 534, vol.17, 1985, Aunt Editing For example, polyvinyl alcohols, alkyl-alkylhydroxysalkyl cellulose, for example, rnethyl cellulose, hydroxypropylcellulose are used, see patents ESP 4,524,194 and ESP 5,087,679. The disadvantage of the wetting agents used in the art is that they remain in the polymer particles and, during the polymer process, lead to discoloration phenomena and / or to the onset of decomposition, see for example Vol. 16, p. 444 of the encyclopedia mentioned above On the other hand, the wetting agents are generally used to reduce the accumulation of polymer in the reactor. Before wetting, it allows the polymerization in organic suspension in the reactors, totally or partially, of metal. In those cases, in the absence of agen + it is wetting, it is very difficult to control the polymerization due to the formation of accumulations in the autoclave. It is known in the art to use alcohols as wetting agents, for example methanol and terbu + anol. However, the tests carried out by the applicant have shown that they can decrease the product of the polymerization (see the examples). The alcohols, in addition, in the case of the recovery of monorres not reacted in the industrial plants, can act mutually with these forming azeotropic compounds, thus making the recovery of the monomers difficult. In addition, the need was felt to have polymerization procedures available that would limit the amount of fine substances (fine polymer powder) to a lesser degree for better handling and accumulation in the reactor. On the other hand, the polymer thus produced should not be discolored and / or "decomposed during the successive steps of the process at high temperatures for sufficiently long and even longer periods than those of the art. The applicant has surprisingly and unexpectedly noticed that the above technical problem has found the solution by using a specific family of nonionic surfactants, defined hereinafter, which allows to reduce to a minimum the amount of fine substances and accumulation in the polymerization of fluorinated polymers which have hydrogen, as defined above, without giving rise to decoration procedures and / or initiating the decomposition in the extruded product at a high temperature. Furthermore, the use of a nonionic surfactant allows, if desired, to recover it from the polymerization phase based on the point "Darkness < _the surfactant agent. An object of the present invention is therefore the use of surfactants in the suspension polymerization of fluorinated monomers to prepare fluoropolymers containing hydrogen, said surfactants having the general formula: Rf 'L- (OCHR1-CHR2) m-OZ wherein: 1 is equal to 1 or 2, preferably i; m is an integer between 4 and 60, preferably between e 8 and 30; L can be selected from: - (CFY-C0-0) p R 'and - (CFY-CO-NH) p', where p is an integer equal to 0 or a 1; Y = F, CF3; R '- a C1-C5 alkyl radical, linear or branched when possible; Ri, R2 can be both H or the first H and the last CH3; both prefer1b1 einen + e H, Z can be H an alkyl radical of Ci-C3, linear or branched when possible, or (FfcJnOH being n an integer of 1 to 6; Rf is a perfluoroalkyl radical or a perfluoropolyether radical, having a number average molecular weight between 250 and 1500, preferably between 400 and 1000.

When the radical Rf is of the perfluoropolyetic type, it comprises repetitive units distributed statistically along the polymer chain selected from: (CF2CF2O), (CFXO) where X is equal to F or CF3, (C3F6O), (CF2 ( CF2)? O) where z is an integer equal to 2 or 3, (CF2CF (0Rf ') 0), (CF (ORf) O) where Rf - is equal to -CF3, -C2F5, -C3F7. When the radical Rf is monovalent, the terminal (T) of the perfluoropolradiate radical is selected from -CF3, -C2F5, -C3F7, C1CF2CF. { CF3) -, CF3CFCICF2-, CICF2CF2-, CICF-2-. Mention may in particular be made of the following perfluoropolyether Rf, as preferred: (a) T-0 (CF2CF (CF3) 0), (CFXO) b-wherein X is F or CF3; a and b are integers such that the molecular weight is included in the scale indicated above; a / b is between 10 and 100; or the repetitive units indicated in subparagraph (a) can be linked together or followed to give a bivalent Rf: -0 (CF2CF (CF3) 0> (CFXO) b -0-CF2 (R'f) "CF -0 - (CF2CF (CF3) 0) a (CFXO) b- wherein R'f is a fluoroalkyl group, for example of the 4 carbon atoms, (b) T-0 (CF2CF2?) C (CF2?) D ( CF2 (CF2)? CF20) h-where c, dyh are numbers such that the molecular weight is included in the scale indicated above, c / d is between 0.1 and 10; h / (c + d) is included in the 0 and 0.05, z has the value indicated above, (b ') 0- (CF2CF20) c (CF201d (CF2)? CF20) h-where c, dyh are numbers such that the molecular weight * is included in the indicated scale above, c / d is between 0.1 and 10, h / (c + d) is between 0 and 0.05, z has the value indicated above, (c) T-0 (CF2CF (CF3) 0) t (CF2CF2? ) f (CFX0) g-where X is F or CF3; e, f, g are numbers such that the molecular weight is included in the scale indicated above; (f + g) is between 0.1 and 10, f / g is comprised between 2 and 10, (c ") -0 (CF2CF (CF3) 0) ß (CF2CF20) f (CFX0) 9-where X is F or CF3; e, i, g are talus numbers that the molecular weight is included in the scale indicated above; e / (f + g) is between 0.1 and 10, f / g is included in + re 2 and 10, (d) T-0 (CF20) j (CF2 CF (0Rf -) 0) (CF Í ORf) 0)? -where Rf "is -CF3, -C2F5, -C3F7; j, k, 1 are numbers such that the molecular weight is included in the scale indicated above; +1 and + + l are at least equal to 2, - / (j + l) is between 0.01 and 1000; l / j is included in re 0.01 and 100; (e) T-0 (CF2 (CF2)? CF20) «- where s is an integer such that of the molecular weight indicated above, z has the meaning already defined, (e ') -0 (CF2 (CF2) zCF2?) ß-where s is an integer such as to give the molecular weight indicated above, and z has the meaning already defined, (f) T-0 (CR.; R5CF2CF2U) j'-wherein R4 and RS "are the same or different one to / to another and are chosen from H, Cl or perfluoroalkyl, for example with 1-4 atoms of carbon, where j 'is an integer such that the molecular weight is as indicated above, said unit being linked within the fluoropolyoxyalkyl chain to one another as follows to have a bivalent radical: - (0CR4RSCF2CF2) P' -O-R ' f -0- (CR «R5CF2CF20) q '-en where R'f is a fluoroalkylene group, for example with 1 to 4 carbon atoms, p 'and q' are integers from 0 to 200, and? '+ q' is at least 1 and such that the molecular weight is indicated above; (g) T-0 (CF (CF3) CF20) j '> - being an integer such as to give the molecular weight indicated above, said units being linked to each other within the fluoropolyxial chain as follows to have a bivalent radical: - (0CF2CF (CF3)). ~ 0-CF2 (R'f) H CF2 -0 (CF (CF3) CF20) b '- where R' f has the meaning indicated above, x is 0 or 1, a 'and b' are integers and a ' + b 'is at least 1 and such that the molecular weight is as indicated above. These compounds and the methods for preparing them are described in GB 1,104,482, USP 3,242,218, USP 3,665,041, USP 3,715,378 and USP 3,665,041, EP 148,482 and USP 4,523,039, USP 5,144,092. The preferred perfluoropolyether radicals of the present invention have the following chemical structure: TO (CF2CF (CF3) 0) n "(0F20) m 'wherein the ratio n" / m' varies from about 20 to about 40, T as defined above. The amount of the surfactant of the present invention generally varies between 0.01-10 g / kg of the reaction medium, preferably between 0.1-3 g / kg. The process of the present invention is generally carried out at a temperature comprised between -30 ° and + -5 ° C, preferably between -10 ° and + 80 ° C, the pressure of the reaction is comprised between broad limits, generally between 1 and 100 bar, preferably between 10 and 40 bar. The reaction medium consists of an organic phase, to which water is usually added in order to favor the dispersion of the heat that occurs during the reaction. The preferred reaction medium comprises water, generally the percentage by weight of the water is 10-90 with respect to the total weight of the medium comprising the onorneros. The organic phase can be constituted by the same ones, without the addition of solvents, or by dissolved solvents in a suitable organic solvent. As organic solvents, chlorofluorocarbons are commonly used, such as CCI2F2 (CFC-12), CCI3F (CFC-11), CCI2FCCIF2 (CFC-113), CC1F2CC1F2 (CFC-114), etc. Since such products have a destructive effect on the ozone present in the stratosphere, alternative products are available, such as the carbon and fluorine containing compounds, which optionally contain hydrogen to obtain the well-known hydrofluorocarbons (HFCs). Hydrofluorocarbons may also contain optional chlorine bleach (HCFC). The above-indicated solvents may optionally contain oxygen. See, for example, U.S. Patent No. 5,182,342. A valid alternative consists of branched chain hydrocarbons, described in USP 5,434,229, which has from 6 to 25 carbon atoms and a ratio between the methyl groups and the number of carbon atoms greater than 0.5, such as by * 2. , 3-d ?? net? Lbutane, 2,3-d? Met? Pentane, 2,2,4-tprnethyl pentane, 2,2,4,6,6-pentamethe ilhep ano, 2,2,4,4, 6-penta ethylheptane, etc, or mixtures thereof. In order to verify the molecular weight of the final product, suitable chain transfer agents can be added to the reaction system, such as: ketones, esters, ethers or aliphatic alcohols having from 3 to 10 carbon atoms; hydrocarbons or halogenated hydrocarbons, having 1 to 6 carbon atoms; bis- (alkyl) carbonates wherein the alkyl has from 1 to 5 carbon atoms; etc. Among them, chloroform, methylcyclopentane and CHCl2CF3 (123) are particularly preferred. EP 673,952 discloses the use of netilcilopentane, and more generally of alkyl-substituted cyclopentanes, with one or more Ci-Cg alkyls, co or chain transfer agents in processes for preparing low temperature fluorinated copolymers containing hydrogen. The transfer agent is sent to the reactor at the beginning of the reaction, continuously or in discrete amounts during the polymerization. The amount of chain transfer agent that is used can vary within fairly broad limits, depending on the type of monomers used, the reaction temperature and the molecular weight to be obtained. Generally, such amount varies between 0.01 and 30% by weight, preferably between 0.05 and 10% by weight with respect to the total amount of the monomers introduced into the reactor. As radical initiators of the polymerization processes of the present invention can be selected those well known in the art, for example: bisacyl peroxides of formula (Rf''C00) 2 r wherein Rf '' 'is a perhalogenoalkyl of Ci -Cio (see for example, EP 185,242, EP 673,951 and USP 4,513,129) or a group of perfluoropolyethers (see for example EP 186,215 and USP 5,021, 516). In this class may be mentioned: bis-dichlorofluoroacetyl peroxide (DCFAP), b-s-tpcloroacetyl peroxide (TCAP); dialkyl peroxydicarbonate with the alkyl of 1 to 8 carbon atoms (see, for example, EP 526,216). Mention may be made of Di-n-propyl peroxydicarbonate and di-isopropyl peroxydicarbonate; dialkyl or diapho peroxides. Mention may be made, for example, of di-tert-butyl peroxide, di-benzoyl peroxide or the like. The amount of initiator generally varies between 0.05 and 10% by weight, preferably between 0.05 and 2% by weight. Hydroporous thermoplastic polymers are all polymers having thermoplastic properties obtainable by homopolymerization of a hydrogenated fluorolefin or copolymeation thereof with a fluorinated (per *) fluoride, or by copolymerization of a per (halogen) fluoroolefin with a completely hydrogenated olefin. One or more fluorinated esters may also be present as modifiers, in amounts comprised between 0.1 and 10 %, for example those indicated in points (1) and (2) below in the present. In particular, the purpose of the process of the present invention can be advantageously employed for: (1) copolymers between a C2-C8 per (halogen) -fluoroolefin, for example TFE or chlorotrifluoroethane (CTFE), and a fully hydrogenated olefin of C2 -Ce, such as, for example, ethylene, propylene or iobutylene, with a r ratio between the fully hydrogenated olefme and the per (halogen) fluoroolefin comprised between 40:60 or 60:40, optionally containing small amounts, generally comprised between 0.1 and 10% by s, of one or more fluorinated compounds, selected, for example between the compounds of formula CX = CFRfo 'wherein X is H or F, Rfo is C1-C10 fluoroalkyl, optionally containing one or more ether groups, for example methyl, ethyl, propyl ether (see for example US Pat. Nos. 4, 513, 129, US-3, 62, 50), or between perfluorodioxoles (see, for example, US-3,865,845, US3,978,030, EP-73,087, EP-76,581, EP-80,187); (2) lead polyvinyl fluoride or polyvinyl fluoride, optionally modified with small amounts, generally ranging from 0.1 to 10% on one or more fluorinated coronomer, such as vinyl fluoride, chlorotrifluoroethylene, hexafluoropropene, tetrafluoroethylene, trifluoroeti log, etc. (see U.S. Patents US-4,524,194 and US-, 739, 024). The following examples are given for illustrative purposes, but are not limiting of the present invention.

EXAMPLE 1 (COMPARATIVE) In an enameled autoclave that has a volume of 18 1 equipped with diverters and agitator that works at 450 rpm in Hatelloy C, 4.3 1 of desalinated water, 1.7 1 (1.36 kg) of methanol, 21 nl of chloroform, 480 g were introduced. of perfluoropropylvinyl ether and 3 kg of chlorotrifluoroethylene. The temperature was maintained at 5 ° C. The ethylene was then introduced to a pressure of 11.35 bar absolute. In the autoclave, the initiator was then introduced gradually, in the form of a solution, maintained at -17 ° C, of pcloroacetyl peroxide (TCAP) in isooctane having the title indicated in the Table. The pressure was maintained constant throughout the polymerization by continuously feeding ethylene in the reactor to a consumption of 300 g. The other reaction parameters and the Melt Flow Rate (TFBF) according to ASTM 3275-89 of the polymer obtained are indicated in the Table. The polymer has a second melting temperature (determined by differential scanning calorimetry, OSO of 234 ° C.

EXAMPLE 2 (COMPARATIVE) Example 1 was repeated except that 1.7 liter of dewatered water was injected instead of ethanol.

EXAMPLE 3 (COMPARATIVE) Example 1 was repeated except that 1.7 liters of desalinated water and 6 g of the following surfactant were introduced instead of methanol: Rf3-C0-NH-CH (CH3) Crb (0CH (CH3) CH2) ai- (OCH2CH2 U? 5 ~ (OCH2CH (CH3)) b 1 NH-CO-Rf3, wherein the + bl equals 2.5, Rf3 and Rf20 (CF2-CF (CF3) 0) n "(CF (CF3) 0) p- (CF20) m'CF2, with Rf3 having a molecular weight of about 650; Rf2 is a perfluoroalkyl having 3 carbon atoms.The values of the tension on the surface (dma / crn) in the water conforming to ASTM D1331-89 of the surfactant indicated above at 25 ° C are 35.5 (in a concentration of 0.01 g / 1) and 25 (in a concentration of g / 1) . The results are indicated in the Table.

EXAMPLE 4 (COMPARATIVE) Example 1 was repeated except that 1.7 liters of demineralized water and 6 g of the following surfactant were introduced, instead of me + anol: CH3 - (CH2)? (0CH2 CH2 OH The results are indicated in the Table.

EXAMPLE 5 Example 1 was repeated except that 1 was introduced. 7 liters of demineralized water and 6 g of the following surfactants, instead of methanol: CF3 - (CF2) sCH2 CH2 CH2 CH2) 8-120H The results are indicated in the Table.

EXAMPLE 6 Example 1 was repeated except that 1.7 ml of deionized water and 6 g of the following surfactants were introduced, instead of methanol: Rf3-C0-NH-CH (CH3) CH2 (0CH (R3) CH2) 22-0CH3 wherein R3 is H, CH3 having a ratio between H / CH3 = 19/3; Rf3 is Rf20 (CF-2-CF (CF3) 0) N (CFICF3) 0) m (CF20) PCF2, having f3 or molecular weight of about 650; Rf2 is a perf1 uoroalkyl of C1-O3. The values of the tension on the surface (dma / cm) in water according to ASTM 1) 1331-89 of the surfactant indicated above at 25 ° C are 35 (in the concentration of 0.01 g / 1) and 25 (in the concentration of 1 g / l) . The results are indicated in the Table.

Claims (5)

NOVELTY OF THE INVENTION CLAIMS

1. Use of surfactants in the suspension polymerization of fluorinated inones to prepare hydrogen-containing ions, having such surfactants the general formula: Rf-f GL- (0CHRI -CHR2) m-0Z] i wherein: i is equal to l or 2, preferably 1; rn is an integer between 4 and 60, preferably between 8 and 30; L can be selected from: - (CFY-CO-O) pR '- and - (CFY-CO-NH) p' -, where p is an integer equal to 0 or a 1; Y = F, CF3; R '= C radical-Cs alkyl radical, linear or branched when possible; Ri, R2 can be both H or the first H and the last CH3; Z can be H, C1-C3 alkyl radical, linear or branched when possible; or (CH2) n0H where n is an integer from 1 to 6; Rf is a perfluoroalkyl radical or a perfluoropolyether radical, having a number average molecular weight between 250 and 1500.

2. Use of surfactants in the suspension poly-radicalization of fluorinated inonomers according to claim 1, further characterized in that the radical Rf is of the perfluoropolyether type and comprises the following repeating units statistically distributed along the polymer chain selected from: (CF2CF20), (CFXO) where X is equal to F or CF3, (C3F6O), (CF2 (CF2) ? O) where z is an integer equal to 2 or 3, (CF2CF (0Rf ') 0), ÍFFORF) 0) where Rf' is equal to -CF3, -C2Fs, -C3F7.

3. Use of surfactants in the suspension polyradiation of fluorinated monomers according to Radiation 2, further characterized in that when Rf is monovalent, a T-terminal of the perfluoropolyether radical is selected from -CF3, -C2F5, -C3F7, C1CF2CF (CF3) -, CF3CFCICF2-, C1CF2CF2-, C1CF2-.

4. Use of surfactants in the suspension polymerization of fluorinated monomers according to claim 3, further characterized in that T is a perfluoroalkyl terminal.

5. Use of surfactants in the suspension polymerization of fluorinated monomers according to claim 2-4, further characterized in that the perfluoropolyether Rf's are selected from the following: (a) T-0 (CF2CF (CF3) 0) a (cfxo) b- where X is F or CF3_; a and b are integers such that the molecular weight is comprised in the scale indicated above a / b is between 10 and 100; or the repetitive units indicated in (a) can be linked as follows to give a bivalent Rf: -0 (CF2CF (CF3) 0) a (CFXO) b -0-CF2 (R'f) "CF2 -0- (CF2CF) (CF3) 0) a (CFX0) b - wherein R'f is a fluoroalkylenic group, having for example 1 to 4 C; (b) T-0- (CF2CF2?) c (CF20) (CF2 (CF2) 2 (CF20) h -where c, dyh are numbers such that the molecular weight is included in the scale indicated above, c / d is between 0.1 and 10, h / (c + d) is between 0 and 0.05, z has the value indicated above, (b ') -0 (CF2CF2?) c (CF20) d (CF2 (CF2) 2 (CF2) ?) h- where c, dyh are numbers such that the molecular weight is included in the scale indicated above; c / d is between 0.1 and 10; h / (c »-d) is between 0 and 0.05 , z has the value indicated above, (c) T-0 (CF2CF (CF3) 0) «(CF2CF20) f (CFXO) a- where X is F or CF3; e, f, g are numbers such that the weight molecular is included in the scale indicated above, e / (f + g) is between 0.1 and 10, f / g is between 2 and 10, (c ') -0 (CF2CF (CF3) 0). (CF2CF20) f (CFXO) g- where X is F or CF3; e, f, g are numbers such that the molecular weight is included in the scale indicated above, e / (f + g) est a between 0.1 and 10, f / g is between 2 and 10, (d) T-0 (CF20) j (CF2CF (0Rf ••) 0)? * (CF (ORf ••) 0)? - in where Rf •• is -CF3, -C2F5, -C3F7; j, k, l are numbers such that the molecular weight is included in the scale indicated above; k + 1 and + k + 1 are at least equal to 2, k / (j + l) is between 0.01 and 1000, 1 / is between 0.01 and 100; (e) T-0 (CF2 (CF2) 2CF2?) ß - where s is an integer such that it gives the molecular weight indicated above, z has the meaning already defined; (e ') -0 (CF2 (CF2) 2CF20) ß - where s is an integer such that of the molecular weight * indicated above, z has the meaning already defined; (f) T-0 (CR "RsCF2CF2?) j j - wherein R" and Rs are the same or different from each other and are selected from H, Cl or perfluoroalkyl, for example with 1-4 C atoms; j 'being an integer such that the molecular weight is as indicated above; said units being linked within the fluoropolyoxyalkylene chain with one another as follows to have a bivalent radical; - (OCR * R5CF2CF2) P '-O-R'f -0- (CR4 RSCF2CF O) ,,' where R'f is a fluoroalkylene group, for example with 1 to 4 C, p 'and q' are numbers integers from 0 to 200, and p '+ q' is at least 1 and such that the molecular weight is as indicated above; (g) T-0 (CF (CF3) CF2?) j •• -, where j "is an integer such as to give the molecular weight indicated above, said units being linked to each other within the fluoropolyxyquinic chain as follows for have a bivalent radical: - (0CF2CF (CF3)) to O-CF2 (R'f)? CF2 -0- (CFICF3) CF2?) b '- where R'f has the meaning indicated above, x is 0 or 1, a 'and b' are integers and a '+ b' is at least 1 and such that the molecular weight is as indicated above 6.- Use of tenectants in the suspension polymerization of fluorinated monomers in accordance with claim 5, further characterized in that the perfluoropolyether radical has the following structure: T0 (CF2CF (CF3) 0) n- (CF20) m '- wherein the ratio n "/ m' varies from about 20 to about 40, where n" and rn 'are integers such as to give the indicated molecular weight antennally 7.- Use of surfactants in the suspension polymerization of fluorinated monomers according to the claims of the 6, further characterized in that the amount of the agent + surfactant ivo per g / kg of the reaction medium varies between 0.01 -10 g / kg. 8. Use of surfactants in the suspension polymerization of fluorinated monomers according to the claims of la la 7, characterized in that the thermoplastic fluoropolymers containing hydrogen and having terrnoplastic properties are obtainable by the ovenpolymerization of a hydrogenated fluoroolefin or the copol uniting the latter with a fluorinated (per) atomizer, or by copolirnection of a fluorinated (halogen) with a completely hydrogenated olefme; one or more fluorinated cononomers may also optionally be present as modifiers, in amounts comprised between 0.1 and 10 mol%. 9. Use of surfactants in the suspension polymerization of fluorinated monomers according to claim 8, further characterized in that the hydrogen-containing fluoropolymers are selected from: (1) copolymers between a per (allogeneic) luoroolefin of C-77 ~ Cß, for example TFE or chlorotrifluoroethylene (CTFE), and a completely hydrogenated olefma of C2-C8, with a molar ratio between fully hydrogenated oleim and per (halogen) -fluoroolefma between 40:60 and 60:40, which optionally contains small amounts, generally comprised between 0.1 and 10% by mole, of one or more fluorinated comonomers, selected from the compounds of formula CX2 = CFRfo, wherein X is H or F, Rfo is a fluoroalkyl of C2-C? or, optionally containing one or more ether groups; ent perfluorodioxoles; (2) polyvinylidene fluoride or polyvinyl fluoride, optionally modified with such amounts, generally comprised between 0.1 and 10 mole%, of 1 or more fluorinated coronomers, such as vmyl fluoride, chlorotri fluoroethylene, hexafluoropropene, tet rafluoroeti log, tp fluoroet i leño. 10. Surfactants according to claims 1-9, further characterized in that Rf is a perfluoropolyether radical.