WO2016124579A1 - (per)fluoropolyether polymers as antifoam agents - Google Patents

(per)fluoropolyether polymers as antifoam agents Download PDF

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Publication number
WO2016124579A1
WO2016124579A1 PCT/EP2016/052157 EP2016052157W WO2016124579A1 WO 2016124579 A1 WO2016124579 A1 WO 2016124579A1 EP 2016052157 W EP2016052157 W EP 2016052157W WO 2016124579 A1 WO2016124579 A1 WO 2016124579A1
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chain
pags
pfpe
formula
group
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French (fr)
Inventor
Patrizia Maccone
Sara Rovinetti
Giovanni Boccaletti
Fabio Riganti
Silvia Rita PETRICCI
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Solvay Specialty Polymers Italy SpA
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Solvay Specialty Polymers Italy SpA
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    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
    • C10M147/00—Lubricating compositions characterised by the additive being a macromolecular compound containing halogen
    • C10M147/04—Monomer containing carbon, hydrogen, halogen and oxygen
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G65/00—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule
    • C08G65/002—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule from unsaturated compounds
    • C08G65/005—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule from unsaturated compounds containing halogens
    • C08G65/007—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule from unsaturated compounds containing halogens containing fluorine
    • C—CHEMISTRY; METALLURGY
    • C14—SKINS; HIDES; PELTS; LEATHER
    • C14C—CHEMICAL TREATMENT OF HIDES, SKINS OR LEATHER, e.g. TANNING, IMPREGNATING, FINISHING; APPARATUS THEREFOR; COMPOSITIONS FOR TANNING
    • C14C11/00—Surface finishing of leather
    • C14C11/003—Surface finishing of leather using macromolecular compounds
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C3/00—Pulping cellulose-containing materials
    • D21C3/22—Other features of pulping processes
    • D21C3/28—Prevention of foam
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H21/00—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
    • D21H21/06—Paper forming aids
    • D21H21/12—Defoamers
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
    • C10M2203/00—Organic non-macromolecular hydrocarbon compounds and hydrocarbon fractions as ingredients in lubricant compositions
    • C10M2203/10—Petroleum or coal fractions, e.g. tars, solvents, bitumen
    • C10M2203/1006—Petroleum or coal fractions, e.g. tars, solvents, bitumen used as base material
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
    • C10M2213/00—Organic macromolecular compounds containing halogen as ingredients in lubricant compositions
    • C10M2213/04—Organic macromolecular compounds containing halogen as ingredients in lubricant compositions obtained from monomers containing carbon, hydrogen, halogen and oxygen
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
    • C10M2213/00—Organic macromolecular compounds containing halogen as ingredients in lubricant compositions
    • C10M2213/06—Perfluoro polymers
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
    • C10N2030/00—Specified physical or chemical properties which is improved by the additive characterising the lubricating composition, e.g. multifunctional additives
    • C10N2030/18—Anti-foaming property
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
    • C10N2040/00—Specified use or application for which the lubricating composition is intended
    • C10N2040/04—Oil-bath; Gear-boxes; Automatic transmissions; Traction drives
    • C10N2040/042—Oil-bath; Gear-boxes; Automatic transmissions; Traction drives for automatic transmissions
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
    • C10N2040/00—Specified use or application for which the lubricating composition is intended
    • C10N2040/08—Hydraulic fluids, e.g. brake-fluids
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
    • C10N2040/00—Specified use or application for which the lubricating composition is intended
    • C10N2040/20—Metal working
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
    • C10N2040/00—Specified use or application for which the lubricating composition is intended
    • C10N2040/25—Internal-combustion engines

Definitions

  • the present invention relates to the use of (per)fluoropolyether polymers as antifoam agents in functional fluid compositions, and compositions comprising the same.
  • Modern mechanical equipment such as a transmission, hydraulic, engine or gear all require a functional fluid to possess a number of different properties. These properties allow the equipment to operate in different harsh environments, including various regimes of soot/sludge formation, friction, corrosion, thermal decomposition, oxidation, extreme pressure and wear.
  • the different properties of the functional fluids are unique to a component of the mechanical equipment. This unique properties may depend on chemical interactions between additives, component design, as well as the materials used. Consequently, a number of functional fluids are required to lubricate various components within the mechanical equipment.
  • Functional fluids are known in the art as compositions comprising at least one oil in admixture with a further ingredient that is selected on the basis of the use intended for the specific functional fluid.
  • functional fluids suffer of a number of disadvantages.
  • bubbles i.e., small gas particles entrained in the fluids greatly influence the performance of functional fluids for hydraulic systems and may cause major problems, such as bulk modulus change, cavitation and aeration, degradation of lubrication, noise generation, oil temperature rise, and deterioration of fluid quality.
  • Foam formation is another common problem in functional fluids.
  • the problem of foam formation has become more important in the last years, because of the diffusion of functional fluids having low and very low viscosity for energy saving.
  • Foam formation is influenced by the chemical and physical properties of the functional fluids and also by the operating conditions (e.g. temperature, viscosity, pressure, circulation rate) or can be caused by the presence of additives.
  • operating conditions e.g. temperature, viscosity, pressure, circulation rate
  • Foam does not circulate in the mechanical equipment and reduces the efficiency of the functional fluid, resulting in drawbacks such as accelerated wear, overheating, cavitation and noise caused by entrained air in the system. Severe foaming can also lead to breakdown of the normal operation of the mechanical equipment.
  • Foam control additives are thus conventionally used in industrial processes where foaming occurs.
  • Foam control additives include both antifoams, i.e. chemical agents that are typically dispersed into the foaming solution to prevent the formation of excessive foam, and defoamers, i.e. substances that are sprayed over and rapidly collapse the existing foam.
  • PFPE perfluoropolyether
  • US 2011/0015420 relates to a perfluoropolyether-modified polysiloxane, which attains a good defoaming effect for organic solvents.
  • US 7,098,173 GENERAL MOTORS CORPORATION relates to an antifoam composition to be used in automatic transmission fluids (ATF), said composition comprising perfluoropolyether compounds.
  • ATF automatic transmission fluids
  • US 2004/0121921 GENERAL MOTORS CORPORATION relates to a functional fluid comprising (a) a lubricating oil, (b) an antiwear agent and (c) an antifoam composition comprising a perfluoropolyether compound.
  • suitable PFPE compounds have the following formulae: R 1 -(CF(CF 3 )-CF 2 -O-) n -R 2 R 1 -(CF 2 -CF 2 -CF 2 -O-) n -R 2 R 1 -(CF 2 -CF 2 -O-) n -(CF 2 -O-) m -R 2 R 1 -(CF 2 -CF(CF 3 )-O-) n -(CF 2 -O-) m -R 2 wherein R 1 and R 2 are functional or non-functional end groups, represented by A 1 -CF 2 O- and -CF 2 A 2 , wherein at least one of A 1 and A 2 comprise functional groups including carboxyl, amide, silane, hydroxyl and phosphate, notably a group of formula -CF 2 -CH 2 (OCH 2 CH 2 ) p OH wherein p is from about
  • PFPE compounds are said to work by being insoluble in ATF.
  • said insolubility leads to some difficulties in formulating the ATF, such as the separation of the phase containing the PFPE compounds in the lubricating composition.
  • This phase separation affects the anti-foam properties of the lubricating composition and, on the other hand, results in a poor shelf-life of the formulation, that must be used immediately and cannot be storage. In practice, this limits the amount of antifoam agent that can be incorporated or dispersed in the ATF.
  • the ATF may be re-dispersed, but the extra-steps creates additional expenses in the manufacturing process.
  • WO WO 2014/067715 SICPA HOLDING SA discloses radiation curable varnishes comprising one or more cationically curable compounds and one or more di-hydroxyl-terminated perfluoropolyether compounds of the general formula HO-(CH 2 CH 2 O) c -CH 2 CF 2 O(CF 2 CF 2 O) a (CF 2 O) b CF 2 CH 2 -(OCH 2 CH 2 ) d OH wherein a and b independently are integers in a range between 0 and 50, wherein a+b ⁇ 1 and wherein c and d may be the same or different and are in the range of 1-20.
  • JP 5780336 DAINIPPON INK AND CHEMICALS discloses a grease base oil diffusion preventing agent comprising a compound with an average molecular mass of 1000 to 3000 and general formula X-CF 2 -(OCF 2 CF 2 ) p -(OCF 2 ) q -OCF 2 -X wherein X is a hydroxymethyl group, p is from 2 to 8, q is from 0 to 30, with p+1 being 3 or greater.
  • the Applicant has perceived that the insolubility of the PFPE compounds in functional fluid composition is a problem for both the manufacturers and the end-users of such functional fluid compositions, in particular in term of shelf-life.
  • the Applicant faced the problem to provide functional fluid compositions, wherein the foam formation is reduced and which do not show phase separation during storage, so as to provide compositions having longer shelf-life.
  • the present invention relates to the use of a (per)fluoropolyether polymer (polymer PFPE-PAGs) as anti-foam agent, said polymer (PFPE-PAGs) comprising a (per)fluoropolyoxyalkylene chain [chain (R f )] having two chain ends, wherein one or both chain end(s) bear(s) a hydroxy-, alkoxy- or acyloxy- terminated polyoxyalkylene chain free from fluorine atoms [chain (R a )], said chain (R a ) comprising from 4 to 50 fluorine-free oxyalkylene units, said units being the same or different each other 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, preferably methyl, ethyl or phenyl, provided that when said chain (R f ) is -(CF
  • said polymer PFPE-PAGs is used as anti-foam agent in a functional fluid composition.
  • the present invention relates to a method for reducing the formation of foam in a functional fluid composition [composition (C)], said method comprising providing a composition (C) comprising at least one lubricant base oils, and adding at least one polymer PFPE-PAGs as defined above to said composition (C).
  • the Applicant has surprisingly found that when the abovementioned polymer PFPE-PAGs are used as anti-foam agents in functional fluid compositions, no separation of the phase comprising the polymer PFPE-PAGs is observed during storage.
  • the Applicant has also found that the abovementioned polymer PFPE-PAGs allow to reduce entrained air and hence bubbles formation, thus improving the air release properties of the functional fluid.
  • the Applicant has found that the abovementioned polymer PFPE-PAGs can be easily added into the final functional fluid composition or into additive packages, without the need of further extra-steps in the manufacturing process.
  • composition (C) comprising at least one polymer PFPE-PAGs as defined above as anti-foam agent, and further ingredients.
  • Polymer PFPE-PAGs will be herein after referred to as “mono- or bi-functional PFPE-PAGs”, depending on whether one or both chain ends bear a chain (R a ).
  • the expression “functional fluid composition” is intended to indicate a fluid composition comprising at least one oil in admixture with a further ingredient that is selected on the basis of the intended use, such as for example metal working fluids, such as cutting oils and coolants; engine oils; gear lubricants; hydraulic fluids; automatic transmission fluids; paints coating and inks; compositions for paper industry, oil recovery, construction industry, jet dyeing of textiles, leather processing, chemical processing; - the term “anti-foam” is intended to indicate the prevention of the formation of foam; - the term “(per)fluoropolyether” is intended to indicate a “fully or partially fluorinated polyether”; - the expression “(per)fluoropolyoxyalkylene chain” is intended to indicate a partially or fully fluorinated, straight or branched, polyoxyalkylene chain; - the term “(halo)alkyl” is intended to indicate a hydrocarbon group wherein one or more hydrogens can be replaced by
  • said chain (R f ) comprises recurring units, which may be equal to or different each other, 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 provision 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 O-, (v) -(CF 2 ) j -CFZ’-O- wherein j is an integer from 0 to 3 and Z’ is a group of general formula -OR f ’T, wherein R f ’ is a fluoropolyoxyalkene chain comprising a number of repeating units from 0 to 10, said recurring units being chosen among the followings
  • said chain (R a ) is terminated with a hydroxyl group, an alkyl group comprising from 1 to 10 carbon atoms, more preferably from 1 to 6 carbon atoms, or an acyloxy group comprising from 1 to 10 carbon atoms, more preferably from 1 to 6 carbon atoms.
  • said chain (R a ) is a hydroxyl group.
  • said chain (R f ) and said chain (R a ) are linked by a group of formula -(CFX) a -D- wherein a is an integer equal to or higher than 1, preferably from 1 to 10, more preferably from 1 to 3; X is F or CF 3 , provided that when a is higher than 1, X is F; D is a divalent alkyl chain comprising from 1 to 20, more preferably from 1 to 6 and even more preferably from 1 to 3 carbon atoms, said alkyl chain being optionally interrupted by at least one oxygen atom and/or optionally substituted with at least one hydroxy group and/or with a perfluoroalkyl group comprising from 1 to 3 carbon atoms.
  • polymer PFPE-PAGs can be represented as follows: -O-D-(CFX) a O(R f )(CFX') b -D * - wherein a, X and D are as defined above b has the same meanings detailed for a, X’ has the same meanings detailed above for X and D* has the same meanings detailed above for D.
  • polymer PFPE-PAGs for the use according to the present invention comply 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, preferably from 500 to 6,000, more preferably from 1000 to 4,000, and comprising, preferably consisting of, repeating units, which may be equal to or different from one another, selected from those of formula (i) to (v) as defined above; - 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
  • chain (R f ) is selected from the following formulae (R f -a) to (R f -c): (R f -a) -(CF 2 O) n (CF 2 CF 2 O) m (CF 2 CF 2 CF 2 O) p (CF 2 CF 2 CF 2 O) q - 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; when m is other than 0, the m/n ratio is preferably between 0.1 and 20; when (m+n) is other than 0, (p+q)/(m+n) is preferably between 0 and 0.2; (R f -b) -(CF 2 CF(CF 3 )O) a (CF
  • Polymers PFPE-PAGs of formula (I) wherein chain (R f ) complies with formula (R f -a) as defined above are particularly preferred in the method of the invention.
  • chain (R a ) complies with the following formula (R a -I): (R a -I) -(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 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, preferably from 4 to 15, more preferably from 4 to 10, and R 1 is selected from hydrogen, C 1 -C 4 straight or branched alkyl, preferably methyl, and -C(O)R 2 , wherein R 2 is C 1 -C 4 straight or branched (halo)alkyl.
  • r is a positive number ranging from 4 to 15, preferably from 4 to 10
  • s is a positive number ranging from 2 to 10, preferably from 4 to 8
  • t and u are 0,and R 1 is selected from hydrogen or methyl.
  • r and s are positive numbers and t and u are 0, r+s ranges from 4 to 20, preferably from 10 to 15, and R 1 is selected from hydrogen or methyl.
  • r, t and u are 0, s is a positive number ranging from 4 to 15, preferably from 4 to 10, and R 1 is selected from hydrogen or methyl.
  • polymer PFPE-PAGs are bifunctional PFPE-PAGs complying 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 as defined above and - R f complies with formula (R f -a) as defined above.
  • polymer PFPE-PAGs are monofunctional PFPE-PAGs complying with formula (I-B) below: A-O-R f -CF 2 -CH 2 -O-R a (I-B) wherein: - A 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, - R a is as defined above and - R f complies with formula (a) as defined above.
  • bifunctional PFPE-PAGs of formula (I-A) are preferred.
  • a preferred group of polymers PFPE-PAGs of formula (I) complies 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, preferably from 500 to 6,000, more preferably from 1,000 to 4,000, and comprising, preferably consisting 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,
  • Preferred chain (R f ) in the PFPE-PAGs of formula (I*) are those selected from formulae (R f -a*) - (R f -c*) here below: (R f -a*) -(CF 2 O) n (CF 2 CF 2 O) m (CF 2 CF 2 CF 2 O) p (CF 2 CF 2 CF 2 O) q - 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; when m is other than 0, the m/n ratio is preferably between 0.1 and 20, more preferably between 0.2 and 10 and even more preferably between 0.5 and 5; when (m+n) is other than 0, (p+q)/(m+n) is preferably between 0 and 0.2; (R f -b*) -(CF 2 CF(CF 3 )O) a (CF 2 CF 2
  • a first group of preferred compounds (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) in which: - R f complies with formulae (R f -a*) – (R f -c*) as defined above; and - R a complies with formula (R a -I*) as defined above.
  • chain R f complies with formula (R f -a*).
  • a second group of compounds (I*) complies with formula (I*-B) below: A-O-R f -CF 2 -CH 2 -O-R a (I*-B) in which: - R f complies with formulae (R f -a*) – (R f -c*) as defined above; and - R a complies with formula (R a -I*) as defined above, and A 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.
  • chain R f complies with formula (R f -a*).
  • Preferred compounds (I*-A) and (I*-B) are those wherein r+s is a positive number ranging from 2 to 20, preferably from 4 to 15, and t and u are 0.
  • R 1 is hydrogen or methyl.
  • the PFPE-PAGs for the use according to the present invention can be obtained for example by reaction of a mono- or bi-functional PFPE alcohol with an alkoxylating agent in such an amount as to obtain from 4 to 50, preferably from 4 to 15, more preferably from 4 to 10, oxyalkylene units at one or both chain ends.
  • the functionality (F) of PFPE-PAGs i.e. the average number of functional groups per molecule of polymer, is from 1 to 2.
  • Bifunctional PFPE-PAGs are more preferred, which have a functionality (F) from 1.5 to 1.95, more preferably from 1.7 to 1.9.
  • the functionality (F) can be calculated for example as disclosed in EP 1810987 A SOLVAY SOLEXIS S.P.A. .
  • the PFPE-PAGs for use in the present invention are synthesised following the process (or “method”) disclosed in international patent application WO WO 2014/090649 SOLVAY SPECIALTY POLYMERS ITALY S.P.A. , which comprises the use of a boron-based catalytic species, wherein sais species is prepared by first providing a mixture of a PFPE alcohol containing a catalytic amount of the corresponding alkoxide and then bringing into contact such mixture with a catalytic amount of a boric acid triester of the same PFPE alcohol.
  • said composition (C) is selected from the group comprising metal working fluids, such as cutting oils and coolants; engine oils; gear lubricants; hydraulic fluids; automatic transmission fluids; shock absorber oils; paints coating and inks; compositions for paper industry, oil recovery, construction industry, jet dyeing of textiles, leather processing, chemical processing.
  • metal working fluids such as cutting oils and coolants; engine oils; gear lubricants; hydraulic fluids; automatic transmission fluids; shock absorber oils; paints coating and inks; compositions for paper industry, oil recovery, construction industry, jet dyeing of textiles, leather processing, chemical processing.
  • composition (C) comprising at least one polymer PFPE-PAGs as defined above as anti-foam agent and further ingredients.
  • said polymer PFPE-PAGs is added to said composition (C) and then a mixing step is performed, for example by high shear mixing.
  • said composition (C) comprises said at least one polymer PFPE-PAGs in an amount of from 0.0001 wt.% (1 ppm) to 3 wt.% based on the total weight of said composition (C), more preferably from 0.0001 wt.% (1 ppm) to less than 2.5 wt.% and even more preferably from 0.0005 wt.% (5 ppm) to 2 wt.%.
  • said polymer PFPE-PAGs complies with formula (I) as defined above.
  • said further ingredients are selected from those commonly used in lubricant compositions, such as lubricant base oils and optionally further additives.
  • Non-limiting examples of lubricant base oils comprise mineral oils, in particular those belonging to Group III (according to American Petroleum Institute – API – classification); to Group (IV) such as polyalphaolefins (PAO) and PAGs; silicon oils; polyphenylethers; etc...
  • Group III according to American Petroleum Institute – API – classification
  • Group IV such as polyalphaolefins (PAO) and PAGs; silicon oils; polyphenylethers; etc...
  • said composition (C) comprises said at least one lubricant base oil in an amount of from 90 to 99.9999 wt.% based on the total weight of said composition (C).
  • Non-limiting examples of additives comprise antirust agents, antioxidants, thermal stabilizers, pour-point depressants, antiwear agents, including those for high pressures, dispersants, tracers, dyestuffs and fillers.
  • dispersants are, for example, surfactants, preferably non-ionic surfactants, more preferably (per)fluoropolyether surfactants and (per)fluoroalkyl surfactants.
  • fillers examples include organic fillers such as polytetrafluoroethylene (PTFE) and inorganic particles such as silica and talc.
  • PTFE polytetrafluoroethylene
  • inorganic particles such as silica and talc.
  • composition (C) is preferably present in composition (C) in an amount of from 0.0001 to 8 wt.% based on the total weight of said composition (C).
  • a solution containing 300 ppm (0.03% by weight) of PFPE-PAG EO/PO was prepared by magnetic stirring 3 g of PFPE-PAG EO/PO in 100 g of mineral oil in a glass vessel over an hotplate at 60°C for 1 h.
  • a solution containing 300 ppm (0.03% by weight) of Fomblin® Y25/6 was prepared by magnetic stirring 3 g of Fomblin® Y25/6 in 100 g of mineral oil in a glass vessel over an hotplate at 60°C for 1 h.

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Abstract

The present invention relates to the use of perfluoropolyether polymers as antifoam agents in functional fluid compositions, and compositions comprising the same.

Description

(Per)fluoropolyether polymers as antifoam agents Cross reference to related applications
This application claims priority from European application No. 15154227.1, filed on 6th February 2015, the whole content of this application being incorporated herein by reference for all purposes.
Technical Field
The present invention relates to the use of (per)fluoropolyether polymers as antifoam agents in functional fluid compositions, and compositions comprising the same.
Background Art
Modern mechanical equipment such as a transmission, hydraulic, engine or gear all require a functional fluid to possess a number of different properties. These properties allow the equipment to operate in different harsh environments, including various regimes of soot/sludge formation, friction, corrosion, thermal decomposition, oxidation, extreme pressure and wear. In many instances the different properties of the functional fluids are unique to a component of the mechanical equipment. This unique properties may depend on chemical interactions between additives, component design, as well as the materials used. Consequently, a number of functional fluids are required to lubricate various components within the mechanical equipment.
Functional fluids are known in the art as compositions comprising at least one oil in admixture with a further ingredient that is selected on the basis of the use intended for the specific functional fluid. However, functional fluids suffer of a number of disadvantages.
For example, bubbles (i.e., small gas particles entrained in the fluids) greatly influence the performance of functional fluids for hydraulic systems and may cause major problems, such as bulk modulus change, cavitation and aeration, degradation of lubrication, noise generation, oil temperature rise, and deterioration of fluid quality.
Foam formation is another common problem in functional fluids. The problem of foam formation has become more important in the last years, because of the diffusion of functional fluids having low and very low viscosity for energy saving.
Foam formation is influenced by the chemical and physical properties of the functional fluids and also by the operating conditions (e.g. temperature, viscosity, pressure, circulation rate) or can be caused by the presence of additives.
Foam does not circulate in the mechanical equipment and reduces the efficiency of the functional fluid, resulting in drawbacks such as accelerated wear, overheating, cavitation and noise caused by entrained air in the system. Severe foaming can also lead to breakdown of the normal operation of the mechanical equipment.
Foam control additives are thus conventionally used in industrial processes where foaming occurs. Foam control additives include both antifoams, i.e. chemical agents that are typically dispersed into the foaming solution to prevent the formation of excessive foam, and defoamers, i.e. substances that are sprayed over and rapidly collapse the existing foam.
Among foam control additives, (per)fluoropolyether (PFPE) polymer derivatives are known in the art.
For example, US 2011/0015420 relates to a perfluoropolyether-modified polysiloxane, which attains a good defoaming effect for organic solvents.
US 7,098,173 GENERAL MOTORS CORPORATION relates to an antifoam composition to be used in automatic transmission fluids (ATF), said composition comprising perfluoropolyether compounds. Also, US 2004/0121921 GENERAL MOTORS CORPORATION relates to a functional fluid comprising (a) a lubricating oil, (b) an antiwear agent and (c) an antifoam composition comprising a perfluoropolyether compound.
In the abovementioned patent and patent application in the name of General Motors Corporation, suitable PFPE compounds have the following formulae:
R1-(CF(CF3)-CF2-O-)n-R2
R1-(CF2-CF2-CF2-O-)n-R2
R1-(CF2-CF2-O-)n-(CF2-O-)m-R2
R1-(CF2-CF(CF3)-O-)n-(CF2-O-)m-R2
wherein R1 and R2 are functional or non-functional end groups, represented by A1-CF2O- and -CF2A2,
wherein at least one of A1 and A2 comprise functional groups including carboxyl, amide, silane, hydroxyl and phosphate, notably a group of formula -CF2-CH2(OCH2CH2)pOH wherein p is from about 1 to about 20.
The abovementioned PFPE compounds are said to work by being insoluble in ATF. However, said insolubility leads to some difficulties in formulating the ATF, such as the separation of the phase containing the PFPE compounds in the lubricating composition. This phase separation, on the one hand, affects the anti-foam properties of the lubricating composition and, on the other hand, results in a poor shelf-life of the formulation, that must be used immediately and cannot be storage. In practice, this limits the amount of antifoam agent that can be incorporated or dispersed in the ATF. Alternatively, the ATF may be re-dispersed, but the extra-steps creates additional expenses in the manufacturing process.
The Applicant is not aware of other patents or patent applications disclosing the use of the PFPE polymers having chain ends comprising alkoxylated end groups as antifoaming additives in functional fluids other than ATF, such as for instance functional fluids for gear boxes, engines, compressors, hydraulics.
WO WO 2014/067715 SICPA HOLDING SA discloses radiation curable varnishes comprising one or more cationically curable compounds and one or more di-hydroxyl-terminated perfluoropolyether compounds of the general formula
HO-(CH2CH2O)c-CH2CF2O(CF2CF2O)a(CF2O)bCF2CH2-(OCH2CH2)dOH
wherein a and b independently are integers in a range between 0 and 50, wherein a+b ≥ 1 and
wherein c and d may be the same or different and are in the range of 1-20.
JP 5780336 DAINIPPON INK AND CHEMICALS discloses a grease base oil diffusion preventing agent comprising a compound with an average molecular mass of 1000 to 3000 and general formula
X-CF2-(OCF2CF2)p-(OCF2)q-OCF2-X
wherein
X is a hydroxymethyl group, p is from 2 to 8, q is from 0 to 30, with p+1 being 3 or greater.
Summary of invention
The Applicant has perceived that the problem of the separation of the phase containing the PFPE compound(s) in functional fluid compositions has not been solved in the art, not even in the abovementioned patent US 7,098,173 and patent application US 2004/0121921 .
Also, the Applicant has perceived that the insolubility of the PFPE compounds in functional fluid composition is a problem for both the manufacturers and the end-users of such functional fluid compositions, in particular in term of shelf-life.
Thus, the Applicant faced the problem to provide functional fluid compositions, wherein the foam formation is reduced and which do not show phase separation during storage, so as to provide compositions having longer shelf-life.
The Applicant has now surprisingly found that the above problem can be solved by using a PFPE polymer (polymer PFPE-PAGs) comprising a (per)fluoropolyether chain having two chain ends, wherein one or both chain ends bear a definite number of oxyalkylene units free from fluorine atoms, as anti-foam agent.
Thus, in a first aspect the present invention relates to the use of a (per)fluoropolyether polymer (polymer PFPE-PAGs) as anti-foam agent, said polymer (PFPE-PAGs) comprising a (per)fluoropolyoxyalkylene chain [chain (Rf)] having two chain ends, wherein one or both chain end(s) bear(s) a hydroxy-, alkoxy- or acyloxy- terminated polyoxyalkylene chain free from fluorine atoms [chain (Ra)], said chain (Ra) comprising from 4 to 50 fluorine-free oxyalkylene units, said units being the same or different each other and being selected from -CH2CH2O- and -CH2CH(J)O-, wherein J is independently straight or branched alkyl or aryl, preferably methyl, ethyl or phenyl,
provided that when said chain (Rf) is
-(CF(CF3)-CF2-O-)n-
-(CF2-CF2-CF2-O-)n-
-(CF2-CF2-O-)n-(CF2-O-)m-
-(CF2-CF(CF3)-O-)n-(CF2-O-)m-, wherein n is at least 3 and the sum n+m is at least 8, none of the two chain ends bears a hydroxy-terminated chain (Ra) comprising from 4 to 20 units of formula -CH2CH2O-.
In a preferred embodiment, said polymer PFPE-PAGs is used as anti-foam agent in a functional fluid composition.
In a second aspect, the present invention relates to a method for reducing the formation of foam in a functional fluid composition [composition (C)], said method comprising providing a composition (C) comprising at least one lubricant base oils, and adding at least one polymer PFPE-PAGs as defined above to said composition (C).
The Applicant has surprisingly found that when the abovementioned polymer PFPE-PAGs are used as anti-foam agents in functional fluid compositions, no separation of the phase comprising the polymer PFPE-PAGs is observed during storage.
The Applicant has also found that the abovementioned polymer PFPE-PAGs allow to reduce entrained air and hence bubbles formation, thus improving the air release properties of the functional fluid.
In addition, the Applicant has found that the abovementioned polymer PFPE-PAGs can be easily added into the final functional fluid composition or into additive packages, without the need of further extra-steps in the manufacturing process.
In a third aspect, the present invention relates a functional fluid composition [composition (C)] comprising at least one polymer PFPE-PAGs as defined above as anti-foam agent, and further ingredients.
Polymer PFPE-PAGs will be herein after referred to as “mono- or bi-functional PFPE-PAGs”, depending on whether one or both chain ends bear a chain (Ra).
Description of embodiments
For the purposes of the present description:
- the expression “functional fluid composition” is intended to indicate a fluid composition comprising at least one oil in admixture with a further ingredient that is selected on the basis of the intended use, such as for example metal working fluids, such as cutting oils and coolants; engine oils; gear lubricants; hydraulic fluids; automatic transmission fluids; paints coating and inks; compositions for paper industry, oil recovery, construction industry, jet dyeing of textiles, leather processing, chemical processing;
- the term “anti-foam” is intended to indicate the prevention of the formation of foam;
- the term “(per)fluoropolyether” is intended to indicate a “fully or partially fluorinated polyether";
- the expression “(per)fluoropolyoxyalkylene chain” is intended to indicate a partially or fully fluorinated, straight or branched, polyoxyalkylene chain;
- the term “(halo)alkyl” is intended to indicate a hydrocarbon group wherein one or more hydrogens can be replaced by one or more halogen atoms, preferably fluorine atoms;
- the use of parentheses before and after symbols or numbers identifying compounds, chemical formulae or parts of formulae has the mere purpose of better distinguishing those symbols or numbers from the rest of the text and hence said parentheses can also be omitted.
In a preferred embodiment, said chain (Rf) comprises recurring units, which may be equal to or different each other, selected from:
(i) -CFXO-, wherein X is F or CF3,
(ii) -CFXCFXO-, wherein X, equal or different at each occurrence, is F or CF3, with the provision that at least one of X is –F,
(iii) -CF2CF2CW2O-, wherein each of W, equal or different from each other, are F or H,
(iv) -CF2CF2CF2CF2O-,
(v) -(CF2)j-CFZ’-O- wherein j is an integer from 0 to 3 and Z’ is a group of general formula -ORf’T, wherein Rf’ is a fluoropolyoxyalkene chain comprising a number of repeating units from 0 to 10, said recurring units being chosen among the followings : -CFXO- , -CF2CFXO-, -CF2CF2CF2O-, -CF2CF2CF2CF2O-, with each of each of X being independently F or CF3 and T being a C1-C3 perfluoroalkyl group.
Preferably, said chain (Ra) is terminated with a hydroxyl group, an alkyl group comprising from 1 to 10 carbon atoms, more preferably from 1 to 6 carbon atoms, or an acyloxy group comprising from 1 to 10 carbon atoms, more preferably from 1 to 6 carbon atoms. In a preferred embodiment, said chain (Ra) is a hydroxyl group.
As it will be apparent to the person skilled in the art, said chain (Rf) and said chain (Ra) are linked by a group of formula -(CFX)a-D-
wherein
a is an integer equal to or higher than 1, preferably from 1 to 10, more preferably from 1 to 3;
X is F or CF3, provided that when a is higher than 1, X is F;
D is a divalent alkyl chain comprising from 1 to 20, more preferably from 1 to 6 and even more preferably from 1 to 3 carbon atoms, said alkyl chain being optionally interrupted by at least one oxygen atom and/or optionally substituted with at least one hydroxy group and/or with a perfluoroalkyl group comprising from 1 to 3 carbon atoms.
Thus, the general structural formula of polymer PFPE-PAGs can be represented as follows:
-O-D-(CFX)aO(Rf)(CFX')b-D*-
wherein
a, X and D are as defined above
b has the same meanings detailed for a,
X’ has the same meanings detailed above for X and
D* has the same meanings detailed above for D.
Preferably, polymer PFPE-PAGs for the use according to the present invention comply with formula (I) below:
A-O-Rf-(CF2)x-CFZ-CH2-O-Ra (I)
wherein:
- Rf is a (per)fluoropolyoxyalkylene chain having an average number molecular weight (Mn) ranging from 100 to 8,000, preferably from 500 to 6,000, more preferably from 1000 to 4,000, and comprising, preferably consisting of, repeating units, which may be equal to or different from one another, selected from those of formula (i) to (v) as defined above;
- Z is fluorine or CF3;
- x is 0 or 1, with the proviso that, when, x is 1, Z is F;
- A is -(CF2)x-CFZ-CH2-O-Ra, wherein x and Z are as defined above, or is a straight or branched C1-C4 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
- Ra is a hydroxy-, alkoxy- or acyloxy- terminated polyoxyalkylene chain free from fluorine atoms [chain (Ra)], said chain Ra being as defined above.
More preferably, in polymer PFPE-PAGs of formula (I) above, chain (Rf) is selected from the following formulae (Rf-a) to (Rf-c):
(Rf-a) -(CF2O)n(CF2CF2O)m(CF2CF2CF2O)p(CF2CF2CF2CF2O)q-
wherein m, n, p, q are 0 or integers selected in such a way as chain Rf meets the above number average molecular weight requirement, with the proviso that if, p and q are simultaneously 0, n is not 0; when m is other than 0, the m/n ratio is preferably between 0.1 and 20; when (m+n) is other than 0, (p+q)/(m+n) is preferably between 0 and 0.2;
(Rf-b) -(CF2CF(CF3)O)a(CF2CF2O)b(CF2O)c(CF(CF3)O)d-
wherein a, b, c, d are 0 or integers selected in such a way as chain Rf meets the above number average molecular weight requirement; with the proviso that, at least one of a, c and d is not 0; when b is other than 0, a/b is preferably between 0.1 and 10; when (a+b) is different from 0 (c+d)/(a+b) preferably is between 0.01 and 0.5, more preferably between 0.01 and 0.2;
(Rf-c) -(CF2CF(CF3)O)e(CF2O)f(CF(CF3)O)g-
wherein e, f, g are 0 or integers selected in such a way as chain Rf meets the above number average molecular weight requirement; when e is other than 0, (f+g)/e is preferably between 0.01 and 0.5, more preferably between 0.01 and 0.2.
Polymers PFPE-PAGs of formula (I) wherein chain (Rf) complies with formula (Rf-a) as defined above are particularly preferred in the method of the invention.
More preferably, in polymer PFPE-PAGs of formula (I) above, chain (Ra) complies with the following formula (Ra-I):
(Ra-I) -(CH2CH2O)r(CH2CH(CH3)O)s(CH2CH(CH2CH3)O)t(CH2CH(Ph)O)uR1
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, preferably from 4 to 15, more preferably from 4 to 10, and R1 is selected from hydrogen, C1-C4 straight or branched alkyl, preferably methyl, and -C(O)R2, wherein R2 is C1-C4 straight or branched (halo)alkyl.
In one preferred embodiment, in the above chain (Ra-I), r is a positive number ranging from 4 to 15, preferably from 4 to 10, s is a positive number ranging from 2 to 10, preferably from 4 to 8, t and u are 0,and R1 is selected from hydrogen or methyl. More preferably, r and s are positive numbers and t and u are 0, r+s ranges from 4 to 20, preferably from 10 to 15, and R1 is selected from hydrogen or methyl.
In another preferred embodiment, r, t and u are 0, s is a positive number ranging from 4 to 15, preferably from 4 to 10, and R1 is selected from hydrogen or methyl.
When two or more of the -CH2CH2O-, -CH2CH(CH3)O-, -CH2CH(CH2CH3)O- and -CH2CH(Ph)O- units are present in chain (Ra-I), they can be arranged in blocks or they can be disposed at random.
According to one preferred embodiment, polymer PFPE-PAGs are bifunctional PFPE-PAGs complying with formula (I-A) below:
Ra-O-CH2-CF2-O-Rf-CF2-CH2-O-Ra (I-A)
wherein:
- Ra is as defined above and
- Rf complies with formula (Rf-a) as defined above.
According to another preferred embodiment, polymer PFPE-PAGs are monofunctional PFPE-PAGs complying with formula (I-B) below:
A-O-Rf-CF2-CH2-O-Ra (I-B)
wherein:
- A is a straight or branched C1-C4 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,
- Ra is as defined above and
- Rf complies with formula (a) as defined above.
In the method of the invention, bifunctional PFPE-PAGs of formula (I-A) are preferred.
A preferred group of polymers PFPE-PAGs of formula (I) complies with formula (I*) below:
A-O-Rf-(CF2)x-CFZ-CH2-O-Ra (I*)
wherein:
- Rf is a (per)fluoropolyoxyalkylene chain having an average number molecular weight Mn ranging from 100 to 8,000, preferably from 500 to 6,000, more preferably from 1,000 to 4,000, and comprising, preferably consisting of, repeating units, which may be equal to or different from one another, selected from
(i) -CFXO-, wherein X is F or CF3,
(ii) -CFXCFXO-, wherein X, equal or different at each occurrence, is F or CF3, with the proviso that at least one of X is –F,
(iii) -CF2CF2CW2O-, wherein each of W, equal or different from each other, are F or H,
(iv) -CF2CF2CF2CF2O-,
(v) -(CF2)j-CFZ’-O- wherein j is an integer from 0 to 3 and Z’ is a group of general formula -ORf’T, wherein Rf’ is a fluoropolyoxyalkene chain comprising a number of repeating units from 0 to 10, said recurring units being chosen among the followings : -CFXO- , -CF2CFXO-, -CF2CF2CF2O-, -CF2CF2CF2CF2O-, with each of each of X being independently F or CF3, and T being a C1-C3 perfluoroalkyl group;
- Z is fluorine or CF3;
- x is 0 or 1, with the proviso that, when, x is 1, Z is F;
- A is (CF2)x-CFZ-CH2-O-Ra, wherein x and Z are as defined above, or is selected from straight or branched C1-C4 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
- Ra complies with the following formula (Ra-I*):
(Ra-I*) -(CH2CH2O)r(CH2CH(CH3)O)s(CH2CH(CH2CH3)O)t(CH2CH(Ph)O)uR1
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, preferably from 4 to 15, more preferably from 4 to 10; and
- R1 is selected from hydrogen, C1-C4 straight or branched alkyl, and -C(O)R2, wherein R2 is C1-C4 straight or branched (halo)alkyl, with the proviso that, when R1 is hydrogen, at least one of s, t and u is not 0.
Preferred chain (Rf) in the PFPE-PAGs of formula (I*) are those selected from formulae (Rf-a*) - (Rf-c*) here below:
(Rf-a*) -(CF2O)n(CF2CF2O)m(CF2CF2CF2O)p(CF2CF2CF2CF2O)q-
wherein m, n, p, q are 0 or integers selected in such a way as chain Rf meets the above number average molecular weight requirement; when m is other than 0, the m/n ratio is preferably between 0.1 and 20, more preferably between 0.2 and 10 and even more preferably between 0.5 and 5; when (m+n) is other than 0, (p+q)/(m+n) is preferably between 0 and 0.2;
(Rf-b*) -(CF2CF(CF3)O)a(CF2CF2O)b(CF2O)c(CF(CF3)O)d-
wherein a, b, c, d are 0 or integers selected in such a way as chain Rf meets the above number average molecular weight requirement; with the proviso that, at least one of a, c and d is not 0; when b is other than 0, a/b is preferably between 0.1 and 10; when (a+b) is different from 0 (c+d)/(a+b) preferably is between 0.01 and 0.5, more preferably between 0.01 and 0.2;
(Rf-c*) -(CF2CF(CF3)O)e(CF2O)f(CF(CF3)O)g-
wherein e, f, g are 0 or integers selected in such a way as chain Rf meets the above number average molecular weight requirement; when e is other than 0, (f+g)/e is preferably between 0.01 and 0.5, more preferably between 0.01 and 0.2.
A first group of preferred compounds (I*) complies with formula (I*-A) below:
Ra-O-CH2-CF2-O-Rf-CF2-CH2-O-Ra (I*-A)
in which:
- Rf complies with formulae (Rf-a*) – (Rf-c*) as defined above; and
- Ra complies with formula (Ra-I*) as defined above.
Preferably, in compounds (I*-A), chain Rf complies with formula (Rf-a*).
A second group of compounds (I*) complies with formula (I*-B) below:
A-O-Rf-CF2-CH2-O-Ra (I*-B)
in which:
- Rf complies with formulae (Rf-a*) – (Rf-c*) as defined above; and
- Ra complies with formula (Ra-I*) as defined above, and A is a straight or branched C1-C4 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.
Preferably, in compounds (I*-B), chain Rf complies with formula (Rf-a*).
Preferred compounds (I*-A) and (I*-B) are those wherein r+s is a positive number ranging from 2 to 20, preferably from 4 to 15, and t and u are 0.
Further preferred compounds (I*-A) and (I*-B) are those wherein r, t and u are 0 and s is a positive number ranging from 4 to 15, preferably from 4 to 10.
Preferably, in compounds (I*-A) and (I*-B), R1 is hydrogen or methyl.
The PFPE-PAGs for the use according to the present invention can be obtained for example by reaction of a mono- or bi-functional PFPE alcohol with an alkoxylating agent in such an amount as to obtain from 4 to 50, preferably from 4 to 15, more preferably from 4 to 10, oxyalkylene units at one or both chain ends.
Preferably, the functionality (F) of PFPE-PAGs, i.e. the average number of functional groups per molecule of polymer, is from 1 to 2. Bifunctional PFPE-PAGs are more preferred, which have a functionality (F) from 1.5 to 1.95, more preferably from 1.7 to 1.9. The functionality (F) can be calculated for example as disclosed in EP 1810987 A SOLVAY SOLEXIS S.P.A. .
Preferably, the PFPE-PAGs for use in the present invention are synthesised following the process (or “method”) disclosed in international patent application WO WO 2014/090649 SOLVAY SPECIALTY POLYMERS ITALY S.P.A. , which comprises the use of a boron-based catalytic species, wherein sais species is prepared by first providing a mixture of a PFPE alcohol containing a catalytic amount of the corresponding alkoxide and then bringing into contact such mixture with a catalytic amount of a boric acid triester of the same PFPE alcohol.
Preferably, said composition (C) is selected from the group comprising metal working fluids, such as cutting oils and coolants; engine oils; gear lubricants; hydraulic fluids; automatic transmission fluids; shock absorber oils; paints coating and inks; compositions for paper industry, oil recovery, construction industry, jet dyeing of textiles, leather processing, chemical processing.
In a third aspect, the present invention relates to a functional fluid composition [composition (C)] comprising at least one polymer PFPE-PAGs as defined above as anti-foam agent and further ingredients.
Preferably, said polymer PFPE-PAGs is added to said composition (C) and then a mixing step is performed, for example by high shear mixing.
Preferably, said composition (C) comprises said at least one polymer PFPE-PAGs in an amount of from 0.0001 wt.% (1 ppm) to 3 wt.% based on the total weight of said composition (C), more preferably from 0.0001 wt.% (1 ppm) to less than 2.5 wt.% and even more preferably from 0.0005 wt.% (5 ppm) to 2 wt.%.
Preferably, said polymer PFPE-PAGs complies with formula (I) as defined above.
Preferably, said further ingredients are selected from those commonly used in lubricant compositions, such as lubricant base oils and optionally further additives.
Non-limiting examples of lubricant base oils comprise mineral oils, in particular those belonging to Group III (according to American Petroleum Institute – API – classification); to Group (IV) such as polyalphaolefins (PAO) and PAGs; silicon oils; polyphenylethers; etc…
Preferably, said composition (C) comprises said at least one lubricant base oil in an amount of from 90 to 99.9999 wt.% based on the total weight of said composition (C).
Non-limiting examples of additives comprise antirust agents, antioxidants, thermal stabilizers, pour-point depressants, antiwear agents, including those for high pressures, dispersants, tracers, dyestuffs and fillers.
Examples of dispersants are, for example, surfactants, preferably non-ionic surfactants, more preferably (per)fluoropolyether surfactants and (per)fluoroalkyl surfactants.
Examples of fillers are organic fillers such as polytetrafluoroethylene (PTFE) and inorganic particles such as silica and talc.
Each of the abovementioned additives is preferably present in composition (C) in an amount of from 0.0001 to 8 wt.% based on the total weight of said composition (C).
Should the disclosure of any patents, patent applications and publications which are incorporated herein by reference conflict with the description of the present application to the extent that it may render a term unclear, the present description shall take precedence.
The invention will be herein after illustrated in greater detail by means of the Examples contained in the following Experimental Section; the Examples are merely illustrative and are by no means to be interpreted as limiting the scope of the invention.
Experimental Section
Materials
Polyethoxy-propoxy-perfluoropolyether PFPE-PAG (hereinafter "PFPE-PAG EO/PO") used in the Example 1 and complying with formula:
HO(CH(CH3)CH2O)s(CH2CH2O)rCH2CF2O-(CF2CF2O)m(CF2O)nCF2CH2(OCH2CH2)r(OCH2CH(CH3))sOH
wherein r = 8.5, s = 4.5, m/n~1, average number molecular weight (Mn) 2,900 and F = 1.8 was manufactured according to the procedure disclosed in WO WO 2014/090649 .
Polyethoxy-perfluoropolyether (hereinafter “PFPE-PAG nEO=7) used in Comparative Example 2 and complying with formula:
HO(CH2CH2O)rCH2CF2O(CF2CF2O)m(CF2O)nCF2CH2(OCH2CH2)rOH
wherein r =7, m/n~1, average number molecular weight (Mn) 2,200 and F = 1.8 was manufactured according to the procedure disclosed in the aforementioned international patent application WO WO 2014/090649 . PFPE-PAG nEO=7 is representative of the PFPE disclosed in prior art document US 7,098,173 GENERAL MOTORS CORPORATION cited above.
Branched perfluropolyether Fomblin ®Y25/6 used in Comparative Example 3 complying with formula:
CF3O(CF2(CF3)CFO)m(CF2O)nCF3
wherein m/n=40/1, average number molecular weight (Mn) 2,400 and kinematic viscosity at 20°C 250 cSt (measured according to ASTM D445).
YUBASE4 from SK lubricants - mineral oil belonging to Group III and having a kinematic viscosity of 5 cSt at 100°C (measured according to ASTM D445).
Example 1
A solution containing 300 ppm (0.03% by weight) of PFPE-PAG EO/PO was prepared by magnetic stirring 3 g of PFPE-PAG EO/PO in 100 g of mineral oil in a glass vessel over an hotplate at 60°C for 1 h.
The solution was analysed by visual inspection after stirring (t=0) and after 24 hours (t=24h). The results are reported in the following Table 1.
Example 2 (comparative example)
A solution containing 300 ppm (0.03% by weight) of PFPE PAG (EO, n=7) was prepared by magnetic stirring 3 g of PFPE PAG (EO, n=7) in 100 g of mineral oil in a glass vessel over an hotplate at 60°C for 1 h.
The solution was analysed by visual inspection after stirring (t=0) and after 24 hours (t=24h). The results are reported in the following Table 1.
Example 3 (comparative example)
A solution containing 300 ppm (0.03% by weight) of Fomblin® Y25/6 was prepared by magnetic stirring 3 g of Fomblin® Y25/6 in 100 g of mineral oil in a glass vessel over an hotplate at 60°C for 1 h.
The solution was analysed by visual inspection after stirring (t=0) and after 24 hours (t=24h). The results are reported in the following Table 1.
Table 1
t=0 t=24h
Example 1 Clear
1 phase		 Clear
1 phase
Example 2(*) Slight opalescent
1 phase		 2 phases
Example 3(*) Opalescent
1 phase		 2 phases
(*) comparative
The above results show that no sediments or phase separation was observed in the solution obtained in Example 1 according to the present invention. Differently, phase separation was observed after 24 hours in the solution obtained according to comparative Example 2 and comparative Example 3.

Claims (15)

  1. Use of a (per)fluoropolyether polymer (polymer PFPE-PAGs) as anti-foam agent, said polymer PFPE-PAGs comprising a (per)fluoropolyoxyalkylene chain [chain (Rf)] having two chain ends, wherein one or both chain end(s) bear(s) a hydroxy-, alkoxy- or acyloxy- terminated polyoxyalkylene chain free from fluorine atoms [chain (Ra)], said chain (Ra) comprising from 4 to 50 fluorine-free oxyalkylene units, said units being the same or different each other and being selected from -CH2CH2O- and -CH2CH(J)O-, wherein J is independently straight or branched alkyl or aryl,
    provided that when said chain (Rf) is
    -(CF(CF3)-CF2-O-)n-
    -(CF2-CF2-CF2-O-)n-
    -(CF2-CF2-O-)n-(CF2-O-)m-
    -(CF2-CF(CF3)-O-)n-(CF2-O-)m-, wherein n is at least 3 and the sum n+m is at least 8, none of the two chain ends bears a hydroxy-terminated chain (Ra) comprising from 4 to 20 units of formula -CH2CH2O-.
  2. The use according to claim 1, wherein said chain (Rf) comprises recurring units, which may be equal to or different each other, selected from:
    (i) -CFXO-, wherein X is F or CF3,
    (ii) -CFXCFXO-, wherein X, equal or different at each occurrence, is F or CF3, with the provision that at least one of X is –F,
    (iii) -CF2CF2CW2O-, wherein each of W, equal or different from each other, are F or H,
    (iv) -CF2CF2CF2CF2O-,
    (v) -(CF2)j-CFZ’-O- wherein j is an integer from 0 to 3 and Z’ is a group of general formula -ORf’T, wherein Rf’ is a fluoropolyoxyalkene chain comprising a number of repeating units from 0 to 10, said recurring units being chosen among the followings : -CFXO- , -CF2CFXO-, -CF2CF2CF2O-, -CF2CF2CF2CF2O-, with each of each of X being independently F or CF3 and T being a C1-C3 perfluoroalkyl group.
  3. The use according to claim 1 or 2, wherein said chain (Rf) and said chain (Ra) are linked by a group of formula -(CFX)a-D-
    wherein
    a is an integer equal to or higher than 1, preferably from 1 to 10, more preferably from 1 to 3;
    X is F or CF3, provided that when a is higher than 1, X is F;
    D is a divalent alkyl chain comprising from 1 to 20, more preferably from 1 to 6 and even more preferably from 1 to 3 carbon atoms, said alkyl chain being optionally interrupted by at least one oxygen atom and/or optionally substituted with at least one hydroxy group and/or with a perfluoroalkyl group comprising from 1 to 3 carbon atoms.
  4. The use according to any one of the preceding claims, wherein said polymer PFPE-PAGs complies with formula (I):
    A-O-Rf-(CF2)x-CFZ-CH2-O-Ra (I)
    wherein:
    - Rf is a (per)fluoropolyoxyalkylene chain having an average number molecular weight (Mn) ranging from 100 to 8,000 and comprising repeating units, which may be equal to or different from one another, selected from those of formula (i) to (v) as defined in claim 2;
    - Z is fluorine or CF3;
    - x is 0 or 1, with the proviso that, when, x is 1, Z is F;
    - A is -(CF2)x-CFZ-CH2-O-Ra, wherein x and Z are as defined above, or is a straight or branched C1-C4 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
    - Ra is a hydroxy-, alkoxy- or acyloxy- terminated polyoxyalkylene chain free from fluorine atoms [chain (Ra)], said chain Ra being as defined in claim 1.
  5. The use according to claim 4, wherein in said formula (I) said chain (Rf) is selected from the following formulae (Rf-a) to (Rf-c):
    (Rf-a) -(CF2O)n(CF2CF2O)m(CF2CF2CF2O)p(CF2CF2CF2CF2O)q-
    wherein m, n, p, q are 0 or integers selected in such a way as chain Rf meets the above number average molecular weight requirement, with the proviso that if, p and q are simultaneously 0, n is not 0; when m is other than 0, the m/n ratio is preferably between 0.1 and 20; when (m+n) is other than 0, (p+q)/(m+n) is preferably between 0 and 0.2;
    (Rf-b) -(CF2CF(CF3)O)a(CF2CF2O)b(CF2O)c(CF(CF3)O)d-
    wherein a, b, c, d are 0 or integers selected in such a way as chain Rf meets the above number average molecular weight requirement; with the proviso that, at least one of a, c and d is not 0; when b is other than 0, a/b is preferably between 0.1 and 10; when (a+b) is different from 0 (c+d)/(a+b) preferably is between 0.01 and 0.5, more preferably between 0.01 and 0.2;
    (Rf-c) -(CF2CF(CF3)O)e(CF2O)f(CF(CF3)O)g-
    wherein e, f, g are 0 or integers selected in such a way as chain Rf meets the above number average molecular weight requirement; when e is other than 0, (f+g)/e is preferably between 0.01 and 0.5, more preferably between 0.01 and 0.2.
  6. The use according to claim 5, wherein in said formula (I) said chain (Ra) complies with the following formula (Ra-I):
    (Ra-I) -(CH2CH2O)r(CH2CH(CH3)O)s(CH2CH(CH2CH3)O)t(CH2CH(Ph)O)uR1
    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 R1 is selected from hydrogen, C1-C4 straight or branched alkyl, preferably methyl, and -C(O)R2, wherein R2 is C1-C4 straight or branched (halo)alkyl.
  7. The use according to claim 6, wherein in chain (Ra-I), r is a positive number ranging from 4 to 15, s is a positive number ranging from 2 to 10, t and u are 0,and R1 is selected from hydrogen or methyl.
  8. The use according to any one of claims 1 to 7, wherein said polymer PFPE-PAGs is a bifunctional PFPE-PAGs.
  9. The use according to claim 8, wherein said bifunctional PFPE-PAGs complies with formula (I-A) below:
    Ra-O-CH2-CF2-O-Rf-CF2-CH2-O-Ra (I-A)
    wherein:
    - Ra is as defined in any one of claims 1, 3 or 5 and
    - Rf complies with formula (Rf-a) as defined in claim 4.
  10. The use according to any one of claim 1 to 7, wherein said polymer PFPE-PAGs is a monofunctional PFPE-PAGs.
  11. The use according to claim 10, wherein said monofunctional PFPE-PAGs complies with formula (I-B) below:
    A-O-Rf-CF2-CH2-O-Ra (I-B)
    wherein:
    - A is a straight or branched C1-C4 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,
    - Ra is as defined in any one of claims 1, 3 or 5 and
    - Rf complies with formula (Rf-a) as defined in claim 4.
  12. A method for reducing the formation of foam in a functional fluid composition [composition (C)], said method comprising providing a composition (C) comprising at least one lubricant base oils, and adding to said functional fluid composition at least one polymer PFPE-PAGs comprising a (per)fluoropolyoxyalkylene chain [chain (Rf)] having two chain ends, wherein one or both chain end(s) bear(s) a hydroxy-, alkoxy- or acyloxy- terminated polyoxyalkylene chain free from fluorine atoms [chain (Ra)], said chain (Ra) comprising from 4 to 50 fluorine-free oxyalkylene units, said units being the same or different each other and being selected from -CH2CH2O- and -CH2CH(J)O-, wherein J is independently straight or branched alkyl or aryl,
    provided that when said chain (Rf) is
    -(CF(CF3)-CF2-O-)n-
    -(CF2-CF2-CF2-O-)n-
    -(CF2-CF2-O-)n-(CF2-O-)m-
    -(CF2-CF(CF3)-O-)n-(CF2-O-)m-, wherein n is at least 3 and the sum n+m is at least 8, none of the two chain ends bears a hydroxy-terminated chain (Ra) comprising from 4 to 20 units of formula -CH2CH2O-.
  13. The method according to claim 12, wherein said functional fluid composition (C) is selected in the group comprising metal working fluids; engine oils; gear lubricants; hydraulic fluids; automatic transmission fluids; shock absorber oils; paints coating and inks; compositions for paper industry, oil recovery, construction industry, jet dyeing of textiles, leather processing, chemical processing.
  14. A composition [composition (C)] comprising at least one polymer PFPE-PAGs as defined in any one of claims 1 to 11 as antifoam agent and optionally further ingredients, wherein said at least one polymer PFPE-PAGs is in an amount of from 0.0001 wt.% (1 ppm) to 3 wt.% based on the total weight of said composition (C).
  15. The composition according to claim 14, wherein said further ingredients are selected in the group lubricant base oils and further additives.
PCT/EP2016/052157 2015-02-06 2016-02-02 (per)fluoropolyether polymers as antifoam agents Ceased WO2016124579A1 (en)

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Cited By (1)

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CN116836750A (en) * 2023-06-27 2023-10-03 大连奥首科技有限公司 Diamond wire cutting fluid, preparation method and application thereof

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US20040121921A1 (en) * 2002-12-20 2004-06-24 Calcut Brent D. Thermally stable antifoam agent and methods for use in functional fluids
WO2014067715A1 (en) * 2012-10-29 2014-05-08 Sicpa Holding Sa Protective coatings for security documents
WO2014090649A1 (en) * 2012-12-11 2014-06-19 Solvay Specialty Polymers Italy S.P.A. Process for the alkoxylation of (per)fluoropolyether alcohols
JP2014156606A (en) * 2014-04-21 2014-08-28 Dic Corp Grease base oil diffusion inhibitor, and grease base oil

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040121921A1 (en) * 2002-12-20 2004-06-24 Calcut Brent D. Thermally stable antifoam agent and methods for use in functional fluids
WO2014067715A1 (en) * 2012-10-29 2014-05-08 Sicpa Holding Sa Protective coatings for security documents
WO2014090649A1 (en) * 2012-12-11 2014-06-19 Solvay Specialty Polymers Italy S.P.A. Process for the alkoxylation of (per)fluoropolyether alcohols
JP2014156606A (en) * 2014-04-21 2014-08-28 Dic Corp Grease base oil diffusion inhibitor, and grease base oil

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116836750A (en) * 2023-06-27 2023-10-03 大连奥首科技有限公司 Diamond wire cutting fluid, preparation method and application thereof

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