Fluorine-based surfactants

Abstract

The present invention provides a perfluoropolyether compound that exhibits excellent surface tension reduction ability and excellent foaming properties and foam stability not only when diluted with freshwater but also with seawater, and a fluorine-based surfactant containing the compound. [Solution] A perfluoropolyetherdicarboxylic acid compound represented by the following formula (1) or a salt thereof. JPEG2026104874000023.jpg21118 (In the formula, Rf1 is a perfluoroalkyl group having 1 to 4 carbon atoms. R 1 R is a substituted or unsubstituted hydrocarbon group having 1 to 10 carbon atoms. 2 R is a substituted or unsubstituted hydrocarbon group having 1 to 6 carbon atoms. 3 and R 4 (where n is an integer from 0 to 5.)

Description

[Technical Field]

[0001] This invention relates to fluorinated surfactants. [Background technology]

[0002] Fluorine-based surfactants have high surface tension-reducing capabilities and, when mixed with fire extinguishing agents, coating compositions, etc., are additives that achieve excellent penetration, wettability, leveling, and surface functionality. Various types of fluorine-based surfactants have been proposed to date. Generally, fluorine-based surfactants consist of compounds that have a perfluoroalkyl group to achieve surface tension-reducing capabilities and a hydrophilic group that contributes to affinity with various compositions within the same molecule.

[0003] Conventional fluorinated surfactants have used linear fluorine with 6 or more carbon atoms, which have high surface orientation and cohesive properties and can reduce surface tension with small amounts of additive. However, with the introduction of fluorine regulations, alternatives to these are being sought.

[0004] Patent Document 1 discloses a betaine-type surfactant with a perfluoropolyether as its main structure. However, the compound described in Patent Document 1 had the drawback of poor foaming ability and foam stability when diluted with seawater. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] U.S. Patent No. 3839425 [Overview of the project] [Problems that the invention aims to solve]

[0006] The present invention provides a perfluoropolyether compound that exhibits excellent surface tension reduction ability and excellent foaming properties and foam stability not only when diluted with freshwater but also when diluted with seawater, and a fluorine-based surfactant containing said compound. [Means for solving the problem]

[0007] In order to solve the above problems, as a result of intensive studies by the present inventors, it has been found that the perfluoropolyether dicarboxylic acid compound represented by the formula (1) exhibits excellent surface tension reducing ability and excellent foaming properties and foam stability not only upon dilution with fresh water but also upon dilution with seawater.

[0008] The present invention has been completed based on these findings and includes inventions in the broad aspects shown below. [Item 1] A perfluoropolyether dicarboxylic acid compound represented by the following formula (1) or a salt thereof. [Chemical formula] (In the formula, Rf1 is a perfluoroalkyl group having 1 to 4 carbon atoms. R 1 is a substituted or unsubstituted hydrocarbon group having 1 to 10 carbon atoms. R 2 is a substituted or unsubstituted hydrocarbon group having 1 to 6 carbon atoms. R 3 and R 4 are the same or different and are substituted or unsubstituted hydrocarbon groups having 1 to 4 carbon atoms. n is an integer of 0 to 5.) [Item 2] The perfluoropolyether dicarboxylic acid compound or a salt thereof according to Item 1, wherein the molecular weight of the perfluoropolyether dicarboxylic acid compound represented by the formula (1) is in the range of 400 to 1700. [Item 3] R 3 and R 4 are the same or different and are linear alkylene groups having 1 to 4 carbon atoms, and the perfluoropolyether dicarboxylic acid compound or a salt thereof according to Item 1 or 2. [Item 4] The perfluoropolyether dicarboxylic acid compound or a salt thereof according to any one of Items 1 to 3, wherein n is an integer of 0 to 3. [Item 5] A fluorosurfactant containing the perfluoropolyether dicarboxylic acid compound or a salt thereof according to any one of Items 1 to 4. [Section 6] A composition comprising a perfluoropolyetherdicarboxylic acid compound or a salt thereof as described in any one of items 1 to 4. [Section 7] A paint containing a perfluoropolyetherdicarboxylic acid compound or a salt thereof as described in any one of items 1 to 4. [Section 8] A fire extinguishing agent containing a perfluoropolyetherdicarboxylic acid compound or a salt thereof as described in any one of items 1 to 4. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a perfluoropolyether compound that exhibits excellent surface tension reduction ability and excellent foaming properties and foam stability not only when diluted with freshwater but also when diluted with seawater, and a fluorine-based surfactant containing said compound. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram illustrating the presumed mechanism by which the compound of the present invention exhibits excellent foaming properties and foam stability when diluted with freshwater. [Figure 2] This is a schematic diagram illustrating the presumed mechanism by which the compound of the present invention exhibits excellent foaming properties and foam stability when diluted with seawater. [Figure 3] The evaluation criteria for foaming properties in the examples are shown below. [Figure 4] The evaluation criteria for foam stability in the examples are shown below. [Figure 5] This is a conceptual diagram showing drainage at the plateau border of foam. [Modes for carrying out the invention]

[0011] The perfluoropolyetherdicarboxylic acid compound according to the present invention is represented by the following formula (1).

[0012] [ka]

[0013] (In the formula, Rf1 is a perfluoroalkyl group having 1 to 4 carbon atoms. R 1 is a substituted or unsubstituted hydrocarbon group having 1 to 10 carbon atoms. R 2 is a substituted or unsubstituted hydrocarbon group having 1 to 6 carbon atoms. R 3 and R 4 are the same or different and are a substituted or unsubstituted hydrocarbon group having 1 to 4 carbon atoms. n is an integer of 0 to 5.) In formula (1), Rf1 is a perfluoroalkyl group having 1 to 4 carbon atoms, and is preferably a linear perfluoroalkyl group having 1 to 4 carbon atoms. By being a linear perfluoroalkyl group, the foaming property and foam stability during seawater dilution can be made better. Examples of the perfluoroalkyl group having 1 to 4 carbon atoms include a trifluoromethyl group, a perfluoroethyl group, a perfluoro-n-propyl group, a perfluoro-isopropyl group, a perfluoro-n-butyl group, a perfluoro-isobutyl group, a perfluoro-sec-butyl group, a perfluoro-tert-butyl group, and the like.

[0014] The -C3F6- in the -(C3F6O) n - part in formula (1) may be -CF2CF2CF2-, may be -CF(CF3)CF2-, may be -CF2CF(CF3)-, but -CF2CF2CF2- or -CF(CF3)CF2- is preferred, and -CF(CF3)CF2- is more preferred.

[0015] The -C2F4- in the -C2F4CO- part in formula (1) may be -CF2CF2- or may be -CF(CF3)-, but -CF(CF3)- is preferred.

[0016] R 1 is a substituted or unsubstituted hydrocarbon group having 1 to 10 carbon atoms. It is preferably a single bond or a substituted or unsubstituted divalent hydrocarbon group having 1 to 8 carbon atoms, and is preferably a single bond or a substituted or unsubstituted divalent hydrocarbon group having 1 to 6 carbon atoms.

[0017] Examples of substituted or unsubstituted divalent hydrocarbon groups having 1 to 10 carbon atoms include substituted or unsubstituted alkylene groups having 1 to 10 carbon atoms, substituted or unsubstituted alkenylene groups having 2 to 10 carbon atoms, substituted or unsubstituted cycloalkylene groups having 4 to 10 carbon atoms, substituted or unsubstituted arylene groups having 6 to 10 carbon atoms, or substituted or unsubstituted aralkylene groups having 7 to 10 carbon atoms.

[0018] Preferably, the group is a substituted or unsubstituted alkylene group having 1 to 8 carbon atoms, a substituted or unsubstituted alkenylene group having 2 to 8 carbon atoms, a substituted or unsubstituted cycloalkylene group having 4 to 8 carbon atoms, a substituted or unsubstituted arylene group having 6 to 8 carbon atoms, or a substituted or unsubstituted aralkylene group having 7 to 8 carbon atoms; more preferably, the group is a substituted or unsubstituted alkylene group having 1 to 6 carbon atoms, a substituted or unsubstituted alkenylene group having 2 to 6 carbon atoms, a substituted or unsubstituted cycloalkylene group having 4 to 6 carbon atoms, or a substituted or unsubstituted arylene group having 6 carbon atoms; even more preferably, the group is a substituted or unsubstituted alkylene group having 1 to 6 carbon atoms, and particularly preferably, the group is an (unsubstituted) alkylene group having 1 to 6 carbon atoms.

[0019] Examples of unsubstituted alkylene groups having 1 to 10 carbon atoms include linear alkylene groups having 1 to 10 carbon atoms (methylene group, ethylene group, trimethylene group, tetramethylene group, pentamethylene group, etc.) and branched alkylene groups having 3 to 10 carbon atoms (1-methylethylene group, 2-methylethylene group, 1-ethylethylene group, 2-ethylethylene group, 1-methylpropylene group, 2-methylpropylene group, 1,1-dimethylpropylene group, 1-hexylpropylene group, 1-hexylbutylene group, 1-octylethylene group, etc.).

[0020] Examples of unsubstituted alkenylene groups having 2 to 10 carbon atoms include linear alkenylene groups having 2 to 10 carbon atoms (ethenylene group, propenylene group, etc.) and branched alkenylene groups having 3 to 10 carbon atoms (1-ethylethenylene group, 1,2-dimethylethenylene group, 1-butylethenylene group, 1-hexylethenylene group, etc.).

[0021] Examples of cycloalkylene groups having 4 to 10 carbon atoms include cyclobutylene, cyclopentylene, 2-methylcyclopentylene, cyclohexylene, 1,3-dimethylcyclohexylene, 1-ethylcyclopentylene, and cyclohexanedimethylene.

[0022] Examples of arylene groups having 6 to 10 carbon atoms include o-, p- or m-phenylene groups, 2,4-naphthylene groups, biphenylene groups, and torylene groups.

[0023] Examples of aralkylene groups having 7 to 10 carbon atoms include phenylmethylene group, diphenylmethine group, 1-phenylethylene group, o-phenyleneethyl group, and naphthylmethylene group.

[0024] R 2 These are identical or different substituted or unsubstituted hydrocarbon groups having 1 to 6 carbon atoms. Preferably, they are substituted or unsubstituted hydrocarbon groups having 1 to 4 carbon atoms, preferably substituted or unsubstituted alkyl groups having 1 to 4 carbon atoms, and more preferably (unsubstituted) alkyl groups having 1 to 4 carbon atoms.

[0025] Examples of hydrocarbon groups having 1 to 6 carbon atoms include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, pentyl, hexyl, allyl, benzyl, cyclopentyl, cyclohexyl, and phenyl groups.

[0026] R 3 and R 4 R is the same or different substituted or unsubstituted hydrocarbon group having 1 to 4 carbon atoms. Preferably it is a substituted or unsubstituted divalent hydrocarbon group having 1 to 4 carbon atoms, preferably a substituted or unsubstituted alkylene group having 1 to 4 carbon atoms, and more preferably a (unsubstituted) linear alkylene group having 1 to 4 carbon atoms. 3 and R 4 It is preferable that they are the same.

[0027] Examples of divalent hydrocarbon groups having 1 to 4 carbon atoms include the methylene group, ethylene group, trimethylene group, tetramethylene group, 1-methylethylene group, 2-methylethylene group, ethenylene group, and propenylene group.

[0028] R 1 ~R 4 In this case, when the hydrocarbon group has substituents, examples of substituents that substitute for hydrogen atoms in the hydrocarbon group include halogen atoms, hydroxyl groups, thiol groups, amide groups, guanidide groups, nitro groups, cyano groups, dialkylamino groups, alkoxy groups, alkylthio groups, aryloxy groups, alkyl halides (the number of halogen atoms is preferably 1 to 10, more preferably 1 to 7. If there are multiple halogen atoms, they may be the same or different), alkylcarbonylamino groups, alkyloxycarbonylamino groups, etc. When the hydrocarbon group has substituents, the number of substituents is preferably 1 to 5, more preferably 1 to 3. Also, if there are multiple substituents, they may be the same or different. Note that the compound represented by formula (1) according to the present invention is a dicarboxylic acid compound and therefore does not contain a carboxyl group as a substituent.

[0029] Examples of the halogen atoms mentioned above include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms.

[0030] The alkyl portion of the dialkylamino group, alkoxy group, alkylthio group, halogenated alkyl group, alkylcarbonylamino group, and alkyloxycarbonylamino group listed above as substituents includes linear or branched alkyl groups having 1 to 12 carbon atoms, such as methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, 1-ethylpentyl group, heptyl group, octyl group, and 2-ethylhexyl group. The number of carbon atoms in the alkyl group is preferably 1 to 8.

[0031] Furthermore, the aryl portion of the aryloxy group listed above as a substituent can be an aryl group having 6 to 10 carbon atoms, such as a phenyl group or a naphthyl group.

[0032] Also, R 1 ~R 4 In this case, as a substituent hydrocarbon group, a divalent group containing at least one heteroatom such as an oxygen atom, nitrogen atom, or sulfur atom may be interposed between the carbon atoms of the hydrocarbon group. The number of heteroatoms can preferably be 1 to 10, more preferably 1 to 6. Examples of divalent groups containing at least one heteroatom include -O-, -N<, -S-, -SO2-, -(C=O)-, -(C=O)O-, -O(C=O)-, -NH(C=O)-, -(C=O)NH-, -NH(C=O)O-, -O(C=O)NH-, etc. When such a divalent group is interposed between the carbon atoms of the hydrocarbon group, the hydrocarbon chain is interrupted by these groups. Also, R 1 ~R 4 In this case, the presence of such a divalent group between the carbon-carbon atoms of the hydrocarbon group results in R 1 ~R 4 The structure may also have a heterocyclic ring.

[0033] In formula (1), n ​​is an integer between 0 and 5. Preferably, n is an integer between 0 and 3, more preferably between 1 and 3, even more preferably 1 or 2, and particularly preferably 1. When n is within the above range, it exhibits excellent surface tension reduction ability. If n exceeds 5, the water solubility of the compound represented by formula (1) may decrease. In one embodiment, from the viewpoint of foaming ability, n is preferably an integer between 0 and 2, more preferably 1 or 2, and particularly preferably 1.

[0034] The molecular weight of the perfluoropolyetherdicarboxylic acid compound represented by formula (1) is preferably 400 to 1700, more preferably 500 to 1500, and even more preferably 600 to 1200.

[0035] Specific examples of perfluoropolyetherdicarboxylic acid compounds represented by formula (1) include, but are not limited to, the following.

[0036] [ka]

[0037] As perfluoropolyetherdicarboxylic acid compounds represented by formula (1), the compounds represented by formulas (1-2), (2-1), (2-2), and (4-2) mentioned above are preferred. Furthermore, the compounds represented by formulas (2-1) and (2-2) are more preferred.

[0038] In one preferred embodiment, the perfluoropolyetherdicarboxylic acid compound represented by formula (1) can be in the form of a salt. Examples of salts include lithium salts, sodium salts, potassium salts, calcium salts, magnesium salts, ammonium salts, alkanolamine salts, and amine salts. Among these, sodium salts and potassium salts are preferred. By forming a salt, hydrophilicity can be increased, and stability in water can be improved.

[0039] The perfluoropolyetherdicarboxylic acid compound represented by formula (1) of the present invention or a salt thereof can be produced, for example, by a method comprising the following steps (i) and (ii): (i) A step of synthesizing an amide compound by reacting a perfluoropolyether compound represented by the following formula (2) with a diamine represented by the following formula (3). (Step ii) A step in which the amide compound obtained in (Step i) is reacted with an alkylcarboxylic acid compound.

[0040] [ka]

[0041] [In the formula, Rf1 is a perfluoroalkyl group having 1 to 4 carbon atoms. 5 [where n is a substituted or unsubstituted hydrocarbon group, and n is an integer between 0 and 5.]

[0042] [ka]

[0043] [In the formula, R 1 R is a substituted or unsubstituted hydrocarbon group having 1 to 10 carbon atoms. 2 These are identical or different substituted or unsubstituted hydrocarbon groups having 1 to 6 carbon atoms. In equation (2), Rf1 and n are the same as those defined in equation (1).

[0044] In equation (2), R 5 is a substituted or unsubstituted hydrocarbon group. Preferably, it is a substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms, more preferably a substituted or unsubstituted hydrocarbon group having 1 to 12 carbon atoms, and particularly preferably a substituted or unsubstituted hydrocarbon group having 1 to 6 carbon atoms.

[0045] Examples of unsubstituted hydrocarbon groups include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, pentyl, hexyl, octyl, allyl, benzyl, cyclopentyl, cyclohexyl, adamantyl, and phenyl groups. Preferably, the group is methyl, ethyl, tert-butyl, or benzyl, with the methyl group being particularly preferred.

[0046] R 5 In this case, if the hydrocarbon group has substituents, the substituents are R of formula (1). 1 ~R 4 The substituents described above can be used without any particular restriction.

[0047] Specific examples of perfluoropolyether compounds represented by formula (2) include, but are not limited to, the following.

[0048] [ka]

[0049] The perfluoropolyether compound represented by formula (2) is available commercially; for example, CAE-500, CAE-600, and CAE-1000 (all manufactured by Sinochem) can be used.

[0050] R in equation (3) 1 , R 2 This is the same as the one defined in equation (1). Specific examples of compounds represented by formula (3) include, for example, N-methylaminoethylamine, N-methylaminopropylamine, N-methylaminobutylamine, N-methylaminopentylamine, N-methylaminohexylamine, N-ethylaminoethylamine, N-ethylaminopropylamine, N-ethylaminobutylamine, N-ethylaminopentylamine, N-ethylaminohexylamine, N-propylaminoethylamine, N-propylaminopropylamine, N-propylaminobutylamine, N-propylaminopentylamine, N-propylaminohexylamine, N-isopropylaminoethylamine, N-isopropylamino Examples include, but are not limited to, propylamine, N-isopropylaminobutylamine, N-isopropylaminopentylamine, N-isopropylaminohexylamine, N-butylaminoethylamine, N-butylaminopropylamine, N-butylaminobutylamine, N-butylaminopentylamine, N-butylaminohexylamine, N-phenylaminoethylamine, N-phenylaminopropylamine, N-phenylaminobutylamine, N-phenylaminopentylamine, N-phenylaminohexylamine, N-(2-hydroxyethyl)ethylenediamine, N-(2-hydroxyethyl)-1,3-propanediamine. Among these, N-methylaminoethylamine, N-methylaminopropylamine, N-ethylaminoethylamine, N-isopropylaminoethylamine, N-butylaminoethylamine, and N-isopropylaminopropylamine are preferred, and N-methylaminoethylamine and N-methylaminopropylamine are more preferred.

[0051] Step i, in which a perfluoropolyether compound represented by formula (2) is reacted with a diamine represented by formula (3), can be represented, for example, by the following reaction equation.

[0052] [ka]

[0053] In the above reaction equation, Rf1, n, and R in the amide compound represented by formula (4) 1 , R 2 This is the same as the one defined in equation (1).

[0054] In the above reaction, the amount of diamine represented by formula (3) used is preferably 1 to 2 moles, and more preferably 1 to 1.5 moles, per mole of the perfluoropolyether compound represented by formula (2).

[0055] The reaction temperature in the above reaction is typically between 0°C and 100°C, or the boiling point of the solvent.

[0056] The reaction time is typically 1 to 48 hours, preferably 1 to 20 hours.

[0057] Examples of reaction solvents include methanol, ethanol, isopropanol, tetrahydrofuran, diethyl ether, ethyl acetate, acetonitrile, acetone, and methyl ethyl ketone. When using a solvent, the amount of solvent used is usually 100 parts by mass or less, preferably 0.2 to 50 parts by mass, per 1 part by mass of the perfluoropolyether compound represented by formula (2). Two or more solvents may be mixed and used as needed.

[0058] If necessary, the reaction may be carried out under an inert gas atmosphere that does not affect the reaction, such as nitrogen, argon, or helium.

[0059] After the reaction is complete, the amide compound represented by formula (4) can be obtained by removing impurities (e.g., unreacted raw materials) by washing with an organic solvent or by concentrating the reaction solution. If necessary, further purification may be performed using known methods.

[0060] The step (step ii) in which the amide compound represented by formula (4) (the amide compound obtained by (step i)) is reacted with an alkylcarboxylic acid compound can be represented, for example, by the following reaction equation.

[0061] [ka]

[0062] In the above reaction equation, R in equation (5) 3 , R in equation (6) 4 This is the same as the one defined in equation (1).

[0063] In formula (5), X1 and in formula (6), X2 are the same or different and represent a leaving group. A leaving group is a group that is eliminated during the reaction and is not particularly limited, but examples include iodine, bromine, chlorine, methylsulfonyloxy group (-OSO2CH3), p-toluenesulfonyloxy group (-OSO2C6H5CH3), trifluoromethylsulfonyloxy group (-OSO2CF3), etc., with bromine or chlorine being preferred.

[0064] In formula (5), M1 and in formula (6), M2 are the same or different, representing a hydrogen atom, an alkali metal, an amine base, or an ammonium base. Examples of alkali metals include lithium, sodium, and potassium. Examples of amine bases include trimethylamine, triethylamine, benzylamine, methylbenzylamine, dimethylbenzylamine, monoethanolamine, diethanolamine, triethanolamine, morpholine, and pyridine.

[0065] The alkylcarboxylic acid compounds represented by formulas (5) and (6) are preferably haloalkylcarboxylic acid salts. Examples of haloalkylcarboxylic acid salts include, but are not limited to, sodium chloroacetate, sodium 3-chloropropionate, sodium 4-chlorobutyrate, sodium 5-chlorovalerate, sodium bromoacetate, sodium 3-bromopropionate, sodium 4-bromobutyrate, and sodium 5-bromovalerate.

[0066] In the above reaction, the total amount of alkylcarboxylic acid compounds represented by formulas (5) and (6) used is preferably 2 to 10 moles, and more preferably 2 to 5 moles, per mole of the amide compound represented by formula (4).

[0067] The above reaction is carried out in the presence of a base. Examples of bases include organic bases such as triethylamine, tributylamine, pyridine, 4-dimethylaminopyridine, diazabicyclononene, and diazabicycloundecene; inorganic bases such as sodium hydride, potassium hydride, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, and cesium carbonate; alkali metal alkoxides such as sodium methoxide, sodium ethoxide, and potassium tert-butoxide; and organolithium compounds such as methyllithium and butyllithium.

[0068] The reaction temperature in the above reaction is typically between 0°C and 100°C, or the boiling point of the solvent.

[0069] The reaction time is typically 1 to 48 hours, preferably 1 to 20 hours.

[0070] Examples of reaction solvents include water, methanol, ethanol, isopropanol, tetrahydrofuran, diethyl ether, ethyl acetate, acetonitrile, acetone, and methyl ethyl ketone. When using a solvent, the amount of solvent used is usually 100 parts by mass or less, preferably 0.5 to 50 parts by mass, per 1 part by mass of the amide compound represented by formula (4). Two or more solvents may be mixed and used as needed.

[0071] If necessary, the reaction may be carried out under an inert gas atmosphere that does not affect the reaction, such as nitrogen, argon, or helium.

[0072] After the reaction is complete, the perfluoropolyetherdicarboxylic acid compound represented by formula (1) can be obtained by removing impurities (e.g., unreacted starting materials) by washing with an organic solvent and concentrating the reaction solution. If necessary, further purification may be performed using known methods.

[0073] Furthermore, salts of perfluoropolyetherdicarboxylic acid compounds represented by formula (1) can be obtained by neutralization with various bases such as sodium hydroxide, lithium hydroxide, potassium hydroxide, and calcium hydroxide.

[0074] A perfluoropolyetherdicarboxylic acid compound represented by formula (1) or a salt thereof can be used as a fluorinated surfactant on its own, but it can also be used as a fluorinated surfactant (fluorinated surfactant composition) which is a composition containing water and / or an organic solvent. The composition may contain one of the perfluoropolyetherdicarboxylic acid compounds represented by formula (1) or a salt thereof alone, or two or more in combination. Various types of water can be used as water, such as pure water, fresh water, or seawater. Examples of organic solvents that can be used include hexylene glycol, isopropyl alcohol, ethylene glycol, N-methylpyrrolidone, N,N-dimethylformamide, propylene glycol monomethyl ether acetate, methyl ethyl ketone, ethyl acetate, n-butyl acetate, etc.

[0075] The content of the perfluoropolyetherdicarboxylic acid compound represented by formula (1) or a salt thereof in the above-mentioned fluorinated surfactant composition is, for example, about 1 to 60 parts by mass, preferably about 10 to 50 parts by mass, per 100 parts by mass of the total amount of the fluorinated surfactant composition.

[0076] The above-mentioned fluorine-based surfactant composition may contain, as appropriate, rust inhibitors, catalysts, antibacterial agents, flame retardants, surfactants, defoaming agents, thickeners, viscosity modifiers, leveling agents, ultraviolet absorbers, preservatives, antifreeze agents, wetting agents, pH adjusters, stabilizers, light-resistant stabilizers, weather-resistant stabilizers, neutralizing agents, matting agents, drying accelerators, foaming agents, non-stick agents, degradation inhibitors, etc., within limits that do not hinder the objectives of the present invention. These may be used individually or in combination of two or more. Each of these additives can be used in an amount ranging from 0.01 to 10 parts by mass per 100 parts by mass of the total amount of the fluorine-based surfactant composition.

[0077] The perfluoropolyetherdicarboxylic acid compound represented by formula (1) of the present invention, or a salt thereof, is useful as a fluorinated surfactant because it has excellent surface tension-reducing ability. The perfluoropolyetherdicarboxylic acid compound represented by formula (1), or a salt thereof, preferably has a surface tension of 30 mN / m or less, and more preferably 20 mN / m or less, when prepared as a 0.1% by mass aqueous solution. A surface tension of 30 mN / m or less provides excellent surface tension-reducing ability. Furthermore, a surface tension of 20 mN / m or less is more preferable because it can be used as a substitute for linear fluorinated surfactants having 6 or more carbon atoms. In this specification, surface tension is measured by the Wilhelmy method (liquid temperature 20°C) as described in the examples.

[0078] Furthermore, the perfluoropolyetherdicarboxylic acid compound or salt thereof of the present invention is useful as a fluorine-based surfactant because it has excellent surface tension-reducing ability even at low concentrations. It is preferable that the aqueous solution concentration of the perfluoropolyetherdicarboxylic acid compound or salt thereof represented by formula (1) is 0.1% by mass or less, and the surface tension of the aqueous solution is 30 mN / m or less. It is even more preferable that the aqueous solution concentration is 0.05% by mass or less, and the surface tension of the aqueous solution is 30 mN / m or less. Having such excellent surface tension-reducing ability even at low concentrations is preferable because it allows for a reduction in the amount of the fluorine-based surfactant of the present invention added when using it as an additive.

[0079] Furthermore, the perfluoropolyetherdicarboxylic acid compounds or salts thereof of the present invention exhibit excellent foaming properties and foam stability when diluted with freshwater and seawater. The reason for these effects is unknown, but the following is expected.

[0080] The compound of the present invention contains two carboxylic acid groups (anionic functional groups) on a hydrophilic group, which is expected to result in strong intermolecular electrostatic repulsion between the hydrophilic groups. Furthermore, it has been observed that the viscosity of the compound increases as the concentration of the active ingredient increases, and tends to decrease when the pH is increased or when a metal salt is added. From this, it is thought that intermolecular interactions such as hydrogen bonding are occurring. Due to such electrostatic repulsion and intermolecular interactions, it is thought that the foaming ability and foam stability are higher compared to monocarboxylic acid type compounds when diluted with freshwater (Figure 1).

[0081] Furthermore, when diluted with seawater, the structure, which has two carboxylic acid groups (anionic functional groups) on the hydrophilic group, is expected to maintain its amphoteric structure even when forming ion pairs with magnesium ions and calcium ions contained in seawater, thereby improving foaming ability. Moreover, in the amphoteric structure formed by ion pairs with magnesium ions and calcium ions, the electrostatic repulsion between the hydrophilic groups is weakened, while the compound of the present invention can be densely adsorbed onto the foam surface. This allows for the formation of a strong foam film with a high fluorine content, resulting in improved foam stability (Figure 2).

[0082] As described above, the perfluoropolyetherdicarboxylic acid compound or salt thereof of the present invention, and the fluorine-based surfactant (fluorine-based surfactant composition) containing the same, have excellent surface tension-reducing properties and can therefore be suitably used as additives to various materials using aqueous solvents or organic solvents, such as paints, fire extinguishing agents, various industrial and commercial cleaning agents, coating materials, and mold release agents.

[0083] For example, when using the perfluoropolyetherdicarboxylic acid compound or a salt thereof of the present invention as an additive for paints, it is preferable to include 0.01 to 10 parts by mass, and more preferably 0.05 to 1 part by mass, of the perfluoropolyetherdicarboxylic acid compound or a salt thereof per 100 parts by mass of the paint composition. If the amount added is within the above range, the surface tension can be sufficiently reduced, and the desired leveling properties can be obtained.

[0084] Furthermore, for example, when using the fluorine-based surfactant of the present invention as an additive for fire extinguishing agents, it is preferable to include 0.01 to 10 parts by mass of the perfluoropolyetherdicarboxylic acid compound or its salt per 100 parts by mass of the fire extinguishing agent composition, and more preferably 0.05 to 1 part by mass. If the amount added is within the above range, the surface tension can be sufficiently reduced, and the desired fire extinguishing effect can be obtained. In addition, even if seawater is used as the solvent (dilution water) to dilute the perfluoropolyetherdicarboxylic acid compound or its salt, excellent foaming properties and foam stability can be observed, and sufficient fire extinguishing performance can be achieved. [Examples]

[0085] The present invention will be further described below with reference to examples, but the present invention is not limited thereto. ( 1 H-NMR analysis conditions) Equipment: JEOL Ltd. JNM-ECZ400S Frequency: 400MHz Deuterated solvent: Deuterated methanol Reference peak: Tetramethylsilane was set to 0.00 ppm.

[0086] (Materials used) • Terminally methylated perfluoropolyethers:

[0087] [ka]

[0088] CAE-500, manufactured by Sinochem: (n=0) Molecular weight 344.08 CAE-600, manufactured by Sinochem: (n=1) Molecular weight 510.10 CAE-1000, manufactured by Sinochem: (n=3) Molecular weight 842.15 • Diamine: NMAEA: N-methylaminoethylamine NMAPA: N-methylaminopropylamine • Haloalkylcarboxylate: Sodium chloroacetate • Comparative example compound 1: Betaine-type surfactant (synthesized according to US 3839425)

[0089] [ka]

[0090] Comparative example compound 2: Anionic surfactant synthesized from CAE-600 and L-tyrosine

[0091] [ka]

[0092] CAE-600 (2.82 g, 0.00553 mol), L-tyrosine (1.00 g, 0.00552 mol), 1,8-diazabicyclo[5.4.0]undecene-7 (1.64 g, 0.0108 mol), and methanol (2.82 g, 0.0881 mol) were added to a 50 mL round-bottom flask containing a stirrer, and the mixture was stirred at 60°C for 2 hours. Hydrochloric acid and metaxylene hexafluoride were added to the reaction mixture, and the reaction mixture was separated into layers. After separating the lower layer, the upper layer was extracted with metaxylene hexafluoride. The lower layer and extract were placed in a round-bottom flask, and the solvent was removed using a rotary evaporator to recover 3.61 g (yield: 99.0%) of the amino acid-modified perfluoropolyether compound.

[0093] Subsequently, the same number of moles of sodium hydroxide as the amino acid-modified perfluoropolyether compound were added to form a sodium salt. Then, water and hexylene glycol were added to adjust the concentration to 30% by mass (water:hexylene glycol = 1:1, by weight ratio) to obtain comparative example compound 2.

[0094] (Synthesis Example 1) Preparation of potassium perfluoropolyetherdicarboxylate salt 1 (Example Compound 1) Potassium perfluoropolyetherdicarboxylate salt 1 (Example compound 1):

[0095] [ka]

[0096] 1. Synthesis of amide compounds using CAE-500 and NMAPA 5.00 g of CAE-500 (0.0145 mol), 1.35 g of NMAPA (0.0153 mol), and 2.53 g of IPA were added to a 50 mL round-bottom flask containing a stirring bar, and the mixture was heated and stirred at 60°C for 3 hours. After cooling, the IPA and unreacted NMAPA were removed by distillation using a rotary evaporator, and 5.33 g (0.0133 mol) of the amide compound was recovered.

[0097] 2. Quaternization of amide compounds In a 50 mL three-necked round-bottom flask equipped with a stirring bar, 5.33 g (0.0133 mol) of the above amide compound, 2.91 g (0.0250 mol) of sodium chloroacetate, 2.50 g of water, and 5.00 g of IPA were added, and the mixture was heated and stirred at the reflux temperature of the solvent for 1 hour. While continuing to heat and stir, 4.98 g (0.0125 mol) of 10 wt% aqueous sodium hydroxide solution was added dropwise. The mixture was heated and stirred for a total of 6 hours.

[0098] Subsequently, 2.91 g (0.0250 mol) of sodium chloroacetate was added to the reaction mixture, and the mixture was heated and stirred at the reflux temperature of the solvent for 1 hour. While continuing to heat and stir, 4.98 g (0.0125 mol) of 10 wt% aqueous sodium hydroxide solution was added dropwise. The mixture was heated and stirred for a total of 6 hours.

[0099] Subsequently, potassium carbonate was added to the reaction mixture and stirred to separate the reaction mixture into layers. After separating the upper layer containing the target product, the solvent was removed using a rotary evaporator, and 6.60 g (0.0131 mol, yield: 98.2%) of Example Compound 1 was recovered.

[0100] The obtained example compound 1 1 The H-NMR results are as follows: 1 H-NMR(CD3OD)δ(ppm):d 1.8-2.1ppm(2H,m), 3.3ppm(3H,s), 3.4-3.6ppm(2H,t), 3.7-3.9ppm(2H,t), 4.1ppm(4H,s)

[0101] (Synthesis Example 2) Preparation of potassium perfluoropolyetherdicarboxylic acid salt 2 (Example Compound 2) Potassium perfluoropolyetherdicarboxylate salt 2 (Example compound 2):

[0102] [ka]

[0103] 1. Synthesis of amide compounds using CAE-600 and NMAEA 5.01 g of CAE-600 (0.00981 mol), 0.775 g of NMAEA (0.0105 mol), and 2.57 g of IPA were added to a 50 mL round-bottom flask containing a stirring bar, and the mixture was heated and stirred at 60°C for 3 hours. After cooling, the IPA and unreacted NMAEA were removed by distillation using a rotary evaporator, and 5.21 g of the amide compound (0.00943 mol) was recovered.

[0104] 2. Quaternization of amide compounds In a 50 mL three-necked round-bottom flask equipped with a stirring bar, 5.21 g (0.00943 mol) of the above amide compound, 2.16 g (0.0181 mol) of sodium chloroacetate, 2.50 g of water, and 5.00 g of IPA were added, and the mixture was heated and stirred at the reflux temperature of the solvent for 1 hour. While continuing to heat and stir, 3.62 g (0.00905 mol) of 10 wt% aqueous sodium hydroxide solution was added dropwise. The mixture was heated and stirred for a total of 6 hours.

[0105] Subsequently, 2.16 g (0.0181 mol) of sodium chloroacetate was added to the reaction mixture, and the mixture was heated and stirred at the reflux temperature of the solvent for 1 hour. While continuing to heat and stir, 3.62 g (0.00905 mol) of 10 wt% aqueous sodium hydroxide solution was added dropwise. The mixture was heated and stirred for a total of 6 hours.

[0106] Subsequently, potassium carbonate was added to the reaction mixture and stirred to separate the reaction mixture into layers. After separating the upper layer containing the target product, the solvent was removed using a rotary evaporator, and 6.38 g (0.00903 mol, yield: 95.7%) of Example Compound 2 was recovered.

[0107] The obtained example compound 2 1 The H-NMR results are as follows: 1 H-NMR(CD3OD)δ(ppm):d 3.1ppm(3H,s), 3.3-3.5ppm(2H,t), 3.6-3.8ppm(2H,t), 4.1ppm(4H,s)

[0108] (Synthesis Example 3) Preparation of potassium perfluoropolyetherdicarboxylic acid salt 3 (Example Compound 3) Potassium perfluoropolyetherdicarboxylate salt 3 (Example compound 3):

[0109] [ka]

[0110] 1. Synthesis of amide compounds using CAE-600 and NMAPA 150 g of CAE-600 (0.297 mol), 27.2 g of NMAPA (0.309 mol), and 75 g of IPA were added to a 500 mL round-bottom flask containing a stirring bar, and the mixture was heated and stirred at 60°C for 3 hours. After cooling, the IPA and unreacted NMAPA were removed by distillation using a rotary evaporator, and 165 g of the amide compound (0.291 mol) was recovered.

[0111] 2. Quaternization of amide compounds In a 1 L three-necked round-bottom flask containing a stirring bar, 100 g (0.177 mol) of the above amide compound, 41.1 g (0.353 mol) of sodium chloroacetate, 50 g of water, and 100 g of IPA were added, and the mixture was heated and stirred at the reflux temperature of the solvent for 1 hour. While continuing to heat and stir, 70.6 g (0.167 mol) of 10 wt% aqueous sodium hydroxide solution was added dropwise. The mixture was heated and stirred for a total of 6 hours.

[0112] Subsequently, 41.1 g (0.353 mol) of sodium chloroacetate was added to the reaction mixture, and the mixture was heated and stirred at the reflux temperature of the solvent for 1 hour. While continuing to heat and stir, 70.6 g (0.167 mol) of 10 wt% aqueous sodium hydroxide solution was added dropwise. The mixture was heated and stirred for a total of 6 hours.

[0113] Subsequently, potassium carbonate was added to the reaction mixture and stirred to separate the reaction mixture into layers. After separating the upper layer containing the target product, the solvent was removed using a rotary evaporator, and 106 g (0.150 mol, yield: 85.0%) of Example Compound 3 was recovered.

[0114] The obtained example compound 3 1 The H-NMR results are as follows: 1 H-NMR(CD3OD)δ(ppm):d 1.8-2.1ppm(2H,m), 3.3ppm(3H,s), 3.4-3.6ppm(2H,t), 3.7-3.9ppm(2H,t), 4.1ppm(4H,s)

[0115] (Synthesis Example 4) Preparation of potassium perfluoropolyetherdicarboxylic acid salt 4 (Example Compound 4) Potassium perfluoropolyetherdicarboxylate 4 (Example Compound 4):

[0116] [ka]

[0117] 1. Synthesis of amide compounds using CAE-1000 and NMAPA 5.00 g of CAE-1000 (0.00739 mol), 0.684 g of NMAPA (0.00776 mol), and 2.74 g of IPA were added to a 50 mL round-bottom flask containing a stirring bar, and the mixture was heated and stirred at 60°C for 3 hours. After cooling, the IPA and unreacted NMAPA were removed by distillation using a rotary evaporator, and 4.97 g (0.00678 mol) of the amide compound was recovered.

[0118] 2. Quaternization of amide compounds In a 1 L three-necked round-bottom flask containing a stirring bar, 4.97 g (0.00678 mol) of the above amide compound, 1.59 g (0.0136 mol) of sodium chloroacetate, 2.50 g of water, and 5.03 g of IPA were added, and the mixture was heated and stirred at the reflux temperature of the solvent for 1 hour. While continuing to heat and stir, 2.73 g (0.00683 mol) of 10 wt% aqueous sodium hydroxide solution was added dropwise. The mixture was heated and stirred for a total of 6 hours.

[0119] Subsequently, 1.59 g (0.0136 mol) of sodium chloroacetate was added to the reaction mixture, and the mixture was heated and stirred at the reflux temperature of the solvent for 1 hour. While continuing to heat and stir, 2.73 g (0.00683 mol) of 10 wt% aqueous sodium hydroxide solution was added dropwise. The mixture was heated and stirred for a total of 6 hours.

[0120] Subsequently, potassium carbonate was added to the reaction mixture and stirred to separate the reaction mixture into layers. After separating the upper layer containing the target product, the solvent was removed using a rotary evaporator, and 5.09 g (0.00574 mol, yield: 84.6%) of Example Compound 4 was recovered.

[0121] The obtained example compound 4 1The H-NMR results are as follows: 1 H-NMR(CD3OD)δ(ppm):d 1.8-2.2ppm(2H,m), 3.3ppm(3H,s), 3.4-3.7ppm(2H,t), 3.8-4.0ppm(2H,t), 4.1ppm(4H,s)

[0122] (Example 1) The example compound 1 synthesized in Synthesis Example 1 was diluted with deionized water to prepare solutions with concentrations of potassium perfluoropolyetherdicarboxylate 1 of 0.05% by mass, 0.1% by mass, and 0.5% by mass in terms of solid content. The surface tension was then measured at each concentration. The results are shown in Table 1.

[0123] Furthermore, Example Compound 1 was diluted with deionized water or synthetic seawater to a solid content of 0.1% by mass to prepare a test solution for foaming and foam stability testing. Then, 50 g of the test solution was added to a 100 mL vial, and the foaming and foam stability were confirmed by the volume of foam immediately after shaking for 1 minute and the change in foam volume after standing at 20°C for 120 minutes. The results are shown in Table 1.

[0124] (Surface tension measurement) Equipment: Surface tension meter DY-300 (manufactured by Kyowa Interface Science Co., Ltd.) Condition: Wilhelmy platinum plating method Liquid temperature: 20℃ Evaluation Criteria ◎:20mN / m or less ○: Greater than 20 mN / m and less than or equal to 30 mN / m △: Greater than 30 mN / m and less than or equal to 40 mN / m ×: Greater than 40 mN / m

[0125] (Evaluation of foaming properties) The criteria for evaluating foaming ability were set as follows, based on the volume of foam immediately after shaking for 1 minute (Figure 3). ◎: The volume of the foam is greater than the volume of the liquid. ○; The volume of the foam is greater than 50% but less than or equal to 100% of the volume of the liquid. △: The volume of the foam is 50% or less of the volume of the liquid. ×: Does not lather.

[0126] (Evaluation of foam stability) The criteria for evaluating foam stability were set as follows, based on the volume percentage of foam after standing at 20°C for 120 minutes, with the volume of foam immediately after shaking for 1 minute set to 100% (Figure 4). ◎: 80% or higher. ○; 60% or more but less than 80%. △: 40% or more but less than 60%. ×: Less than 40%.

[0127] (Examples 2-4, Comparative Examples 1, 2) Except for using the compounds listed in Table 1, surface tension, foaming ability, and foam stability were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0128] [Table 1]

[0129] The results from Examples 1 to 4 clearly demonstrate that the compounds of the present invention possess excellent surface tension reduction capabilities. In particular, the compounds of Examples 2 and 3 (with n=1 repeating unit of the perfluoropolyether moiety) were found to exhibit superior surface tension reduction capabilities compared to the compounds of Examples 1 and 4.

[0130] Furthermore, the results from Examples 1-4 showed that the compounds in Examples 1-3, in particular, exhibited high foaming properties when diluted with deionized water and synthetic seawater. The reason for this effect is unknown, but the following is expected: Foaming properties are influenced by the adsorption rate of the surfactant to the air incorporated into the liquid. The perfluoropolyether chain of the compound used in Example 4 is longer than that of the compounds in Examples 1-3, and the molecule is bent via the ether, which is thought to make it difficult to increase the adsorption density at the foam film interface and result in a lower adsorption rate. As a result, the compound in Example 4 exhibits lower foaming properties compared to the compounds in Examples 1-3.

[0131] Furthermore, the results from Examples 1-4 showed that all compounds exhibited high foam stability when diluted with deionized water and synthetic seawater. In particular, the compounds in Examples 2 and 3 showed higher foam stability compared to the compounds in Examples 1 and 4. The reason for this effect is unknown, but the following is expected. One factor influencing foam stability is liquid suction at the plateau border (the part where the foam is in contact) (Figure 5). At the plateau border, the pressure difference between the inside of the foam and the lamellae causes liquid to flow (drain) towards the lamellae with lower pressure, resulting in a thinner foam film. Here, the pressure difference between the inside of the foam and the lamellae depends on the radius of curvature of the interface and the surface tension of the liquid, as shown in Laplace's equation below. It is presumed that the compounds in Examples 2 and 3 have lower solution surface tension than the compounds in Examples 1 and 4, resulting in a smaller pressure difference between the inside of the foam and the lamellae, which delays drainage and thus improves foam stability.

[0132]

number

Claims

1. A method for producing a perfluoropolyetherdicarboxylic acid compound represented by the following formula (1) or a salt thereof, Step i: A step of synthesizing an amide compound by reacting a perfluoropolyether compound represented by the following formula (2) with a diamine represented by the following formula (3). Step ii: A step of reacting the amide compound obtained in step i with at least one of the alkylcarboxylic acid compounds represented by the following formulas (5) and (6). A manufacturing method that includes this. 【Chemistry 1】 (wherein, Rf １ R is a perfluoroalkyl group having 1 to 4 carbon atoms. １ R is a substituted or unsubstituted hydrocarbon group having 1 to 10 carbon atoms. ２ R is a substituted or unsubstituted hydrocarbon group having 1 to 6 carbon atoms. ３ and R ４ (These are identical or different substituted or unsubstituted hydrocarbon groups having 1 to 4 carbon atoms. n is an integer from 0 to 5.) 【Chemistry 2】 (wherein, Rf １ , n is defined as in equation (1). R ５ (This refers to a substituted or unsubstituted hydrocarbon group.) 【Transformation 3】 (wherein, R １ , R ２ is as defined in formula (1).) 【Chemistry 4】 (In the formula, R ３ This is defined as shown in equation (1). X １ This indicates a leaving group. １ (This represents a hydrogen atom, alkali metal, amine base, or ammonium base.) 【Transformation 5】 (In the formula, R ４ This is defined as shown in equation (1). X ２ This indicates a leaving group. ２ (This represents a hydrogen atom, alkali metal, amine base, or ammonium base.)

2. In the reaction in step i, the amount of diamine used is 1 to 2 moles per mole of the perfluoropolyether compound. In the reaction in step ii, the total amount of alkylcarboxylic acid compound used is 2 to 10 moles per mole of the amide compound. The manufacturing method according to claim 1.

3. The molecular weight of the perfluoropolyetherdicarboxylic acid compound is in the range of 400 to 1700. The manufacturing method according to claim 1.

4. R ３ and R ４ However, they are the same or different linear alkylene groups having 1 to 4 carbon atoms. The manufacturing method according to claim 1.

5. The manufacturing method according to claim 1, wherein n is an integer from 0 to 3.

6. The process includes obtaining a perfluoropolyetherdicarboxylic acid compound or a salt thereof by the manufacturing method described in claim 1, A method for producing a fluorine-based surfactant containing a perfluoropolyetherdicarboxylic acid compound or a salt thereof.

7. The process includes obtaining a perfluoropolyetherdicarboxylic acid compound or a salt thereof by the manufacturing method described in claim 1, A method for producing a composition containing a perfluoropolyetherdicarboxylic acid compound or a salt thereof.

8. The process includes obtaining a perfluoropolyetherdicarboxylic acid compound or a salt thereof by the manufacturing method described in claim 1, A method for producing a paint containing a perfluoropolyetherdicarboxylic acid compound or a salt thereof.

9. The process includes obtaining a perfluoropolyetherdicarboxylic acid compound or a salt thereof by the manufacturing method described in claim 1, A method for producing a fire extinguishing agent containing a perfluoropolyetherdicarboxylic acid compound or a salt thereof.

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