Polymers, resin compositions, dispersants, and lubricant compositions

Abstract

The present invention provides a polymer that has high dispersibility of fluororesin particles and excellent solubility in fluorine-based solvents, and further has a perfluoroalkyl group having less than 6 carbon atoms, which imposes little burden on the environment and living organisms. The polymer contains at least two structural units of first to third monomer units, or is composed solely of the second monomer unit. The first to third monomer units are represented by formulas (1) to (3), respectively. CH2=CR 1 -COO-Q 1 -Rf 1 (1) R 1 :H or methyl, Rf 1 : C1-4 polyfluoroalkyl group, Q 1 :Single bond, etc. CH2=CR 2 -COO-R 3 -Q 2 -Rf 2 (2) R 2 :H or methyl, R 3 : C1-6 alkylene group, Rf 2 : C5-20 perfluoropolyether group, Q 2 : Single bond or -NH-COO-Q 21 - and Q 21 is a single bond, etc. CH2=CR 4 -COO-Q 3 -R 5 (3) R 4 :H or methyl, R 5 : C12 to C40 alkyl group, Q 3 :Single bond, etc.

Description

[Technical Field]

[0001] The present invention relates to polymers, resin compositions, dispersants, and lubricant compositions. [Background technology]

[0002] In general, fluororesin particles such as polytetrafluoroethylene (PTFE) are known to have excellent heat resistance, chemical resistance, lubricity, water repellency, oil repellency, etc., but have poor dispersibility in solvents. For example, Patent Document 1 discloses a dispersant that disperses fluororesin particles in mineral oil or the like. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-105627 Summary of the Invention [Problem to be solved by the invention]

[0004] The dispersant described in Patent Document 1 is a composition containing a compound containing a perfluoroalkyl group having six or more carbon atoms. These dispersants are known to have excellent dispersibility, but in recent years, one type of this compound, PFHxS (Perfluorohexanesulfonic acid), its salts, and PFHxS-related substances, have been designated as Type 1 Specified Chemical Substances under the Act on the Examination and Regulation of Chemical Substances, etc., due to their adverse effects on the environment and living organisms. As a result, their manufacture, import, and use are prohibited in principle.

[0005] In addition, as with PFHxS, its salts, and PFHxS-related substances, which are one of the above compounds, it has been decided that the use of these compounds will be gradually restricted from 2026, in consideration of their impact on the environment and living organisms.

[0006] On the other hand, fluorine-based solvents are sometimes used as solvents for dispersing fluororesin particles because of their low flammability, quick-drying properties, and low risk of chemical attack, and there is a demand for the development of dispersants for dispersing fluororesin particles in fluorine-based solvents. A dispersant for dispersing fluororesin particles in a fluorine-based solvent is required to have high dispersibility and high solubility in the fluorine-based solvent. In other words, there is a need to develop a dispersant for fluororesin particles that has low environmental and biological impact and is highly soluble in fluorine-based solvents.

[0007] The present invention has been made in view of the above circumstances, and provides a polymer that has high dispersibility of fluororesin particles and excellent solubility in fluorine-based solvents, and further has a perfluoroalkyl group having less than 6 carbon atoms, which imposes little burden on the environment and living organisms.

[0008] As a result of extensive investigations to solve the above problems, the present inventors have found that when a polymer having a specific composition is used as a dispersant, the dispersant has excellent dispersibility of fluororesin particles in fluorine-based solvents and solubility in fluorine-based solvents, and have thus completed the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] The following describes embodiments of the present invention. The various features shown in the following embodiments can be combined with each other. Furthermore, each feature can be an independent invention. Furthermore, in the following embodiments, elements not specified in the claims are optional elements and can be omitted.

[0010] 1. Polymer A polymer according to one embodiment of the present invention (hereinafter also referred to as "polymer A") contains at least two structural units, namely, a first monomer unit, a second monomer unit, and a third monomer unit, or is composed solely of the second monomer unit (contains only the second monomer unit as a monomer unit).

[0011] Polymer A preferably contains 5 to 90 mass %, more preferably 10 to 80 mass %, of the first monomer unit relative to 100 mass % of the monomer units constituting the polymer.

[0012] Polymer A preferably contains 5 to 100% by mass of the second monomer unit relative to 100% by mass of the monomer units constituting the polymer. When polymer A contains at least one of the first monomer unit and the third monomer unit in addition to the second monomer unit, it preferably contains 10 to 90% by mass, more preferably 40 to 70% by mass of the second monomer unit.

[0013] Polymer A preferably contains 5 to 50% by mass, and more preferably 10 to 30% by mass, of the third monomer unit relative to 100% by mass of the monomer units constituting the polymer.

[0014] In one embodiment of the present invention, polymer A may have a structure containing first and third monomer units, and preferably has a structure containing only first and third monomer units as monomer units. In this case, polymer A preferably contains 60 to 90 mass% of first monomer units and 10 to 40 mass% of third monomer units, and more preferably contains 70 to 80 mass% of first monomer units and 20 to 30 mass% of third monomer units, relative to 100 mass% of monomer units constituting the polymer.

[0015] In one embodiment of the present invention, polymer A may have a structure containing second and third monomer units, and preferably has a structure containing only second and third monomer units as monomer units. In this case, polymer A contains preferably 60 to 90% by mass of second monomer units and preferably 10 to 40% by mass of third monomer units, and more preferably 70 to 80% by mass of second monomer units and 20 to 30% by mass of third monomer units, relative to 100% by mass of the monomer units constituting the polymer.

[0016] In one embodiment of the present invention, polymer A may have a structure containing first, second, and third monomer units, and preferably has a structure containing only first, second, and third monomer units as monomer units. In this case, polymer A contains, relative to 100% by mass of the monomer units constituting the polymer, preferably 5 to 90% by mass of the first monomer units, preferably 5 to 90% by mass of the second monomer units, and preferably 5 to 30% by mass of the third monomer units, more preferably 15 to 40% by mass of the first monomer units, 40 to 60% by mass of the second monomer units, and 20 to 30% by mass of the third monomer units.

[0017] In one embodiment of the present invention, polymer A may have a structure consisting solely of second monomer units as monomer units. When polymer A contains only second monomer units as monomer units, the second monomer units account for 100% by mass of 100% by mass of the monomer units constituting the polymer.

[0018] The weight-average molecular weight of polymer A is preferably 120,000 or less, more preferably 50,000 or less, and even more preferably 30,000 or less. The weight-average molecular weight can be determined by gel permeation chromatography using a polystyrene equivalent value, etc. When the weight-average molecular weight is 120,000 or less, a polymer having excellent dispersibility and solubility in fluorine-based solvents can be obtained.

[0019] 1-1. First monomer unit The first monomer unit in this embodiment is a structural unit derived from a first monomer represented by the following formula (1). CH2=CR 1 -COO-Q 1 -Rf 1 (1) In formula (1), R 1 is a hydrogen atom or a methyl group, and Rf 1 is a perfluoroalkyl group having 1 to 4 carbon atoms, and Q 1 is a single bond or a divalent linking group. 1 is preferably a methyl group.

[0020] Rf 1 The number of carbon atoms in the perfluoroalkyl group in Rf is 4 or less. If the number of carbon atoms in the perfluoroalkyl group is 6 or more, it is subject to PFHxS and PFHxA regulations, and its use is restricted. 1 may be a linear, branched, or cyclic perfluoroalkyl group, and is preferably a linear perfluoroalkyl group. Specific examples of the linear perfluoroalkyl group include CF3-, CF3CF2-, CF3CF2CF2-, and CF3CF2CF2CF2-.

[0021] Q 1 The divalent linking group in is not particularly limited, and examples thereof include an alkylene group having 1 to 5 carbon atoms (a linear or branched alkylene group which may have an alkyl group or the like as a substituent), a carbonyl group, an ester bond, a urethane bond, an amide bond, etc. These linking groups may be of one type or a combination of two or more types. 1 is preferably a linking group having a chain length of 1 to 5 carbon atoms. 1 is preferably an alkylene group, for example, -CH2-, -CH2CH2-, -CH2CH2CH2-, -CH2CH2CH2CH2-, etc., and particularly preferably -CH2CH2-.

[0022] Examples of the compound represented by formula (1) include 2-(perfluorobutyl)ethyl methacrylate, 2-(perfluorobutyl)ethyl acrylate, 1H,1H,5H-octafluoropentyl acrylate, 1H,1H-pentafluoropropyl methacrylate, and 3-(perfluorobutyl)-2-hydroxypropyl acrylate. Among these, 2-(perfluorobutyl)ethyl methacrylate and 2-(perfluorobutyl)ethyl acrylate are particularly preferred. Polymer A may contain, as the first monomer unit, one or more structural units derived from these monomers.

[0023] 1-2. Second monomer unit The second monomer unit in one embodiment of the present invention is a structural unit derived from a second monomer represented by the following formula (2).

[0024] CH2=CR 2 -COO-R 3 -Q 2 -Rf 2 (2) In formula (2), R 2 is a hydrogen atom or a methyl group, and R 3 is an alkylene group having 1 to 6 carbon atoms, and Rf 2 is a perfluoropolyether group having 5 to 20 carbon atoms, Q 2 is a linking group containing a single bond (direct bond) or a urethane bond (-NH-COO-). 2 is preferably a methyl group (-CH3).

[0025] R 3 is an alkylene group having 1 to 6 carbon atoms, preferably an alkylene group having 1 to 3 carbon atoms, and more preferably an alkylene group having 1 to 2 carbon atoms. 3 R may be a linear or branched alkylene group, and is preferably a linear alkylene group. 3 R may have a substituent, but is preferably an alkylene group that does not have a substituent (particularly does not have a fluorine atom). 3 Specifically, is -CH2- or -CH2CH2-, etc.

[0026] Rf 2 Rf may be a linear or branched perfluoropolyether group, and is preferably a branched perfluoropolyether group. 2 may be composed of a perfluorooxyalkylene group or perfluorooxyalkyl group (terminal) having one or more carbon atoms, but each perfluorooxyalkylene group and perfluorooxyalkyl group preferably has five or less carbon atoms, more preferably four or less carbon atoms.

[0027] Rf 2 can be a perfluoropolyether group represented by the following formula (4): F(CF2CF2O) b (CF(CF3)CF2O) c (CF2O) d (CF2CF2CF2O) e (CF2CF2CF2CF2O) f ···(4) In formula (4), b, c, d, e, and f each independently represent 0 or an integer of 1 or greater, and b+c+d+e+f is 2 to 20. The bonding order of the repeating units of (CF2CF2O), (CF(CF3)CF2O), (CF2O), (CF2CF2CF2O), and (CF2CF2CF2CF2O) is not limited, and they may be bonded to each other randomly or in blocks.

[0028] Rf 2 The number of carbon atoms (the number of carbon atoms contained in the entire perfluoropolyether group) is preferably 5 to 20, and more preferably 8 to 20.

[0029] In one embodiment, polymer A comprises a second monomer unit and Rf 2 The alkyl group may be a perfluoropolyether having 8 to 20 carbon atoms.

[0030] Q 2 is a linking group containing a single bond or a urethane bond (-NH-COO-Q 21 where Q 21 is a single bond or an alkylene group. In the alkylene group, some of the hydrogen atoms may be substituted with fluorine atoms. 2 is preferably a single bond or a linking group having 1 to 5 carbon atoms, preferably 1 to 3 carbon atoms. 2 More specifically, examples of the alkyl group include a single bond, -NH-COO-, -NH-COO-CH2-, -NH-COO-CH2-CH2-, and the like.

[0031] Examples of the compound represented by formula (2) include PFPE (HFPO trimer) methacrylate, PFPE (HFPO hexamer) methacrylate, fluorinated triethylene glycol monobutyl urethane acrylate, and fluorinated triethylene glycol monobutyl urethane methacrylate.

[0032] 1-3.Third monomer unit The third monomer unit in this embodiment is a structural unit derived from a third monomer represented by the following formula (3). CH2=CR 4 -COO-Q 3 -R 5 (3) In formula (3), R 4 is a hydrogen atom or a methyl group, R 5 is an alkyl group with 12 to 40 carbon atoms, Q 3 is a single bond (direct bond) or a divalent linking group. 4 is preferably a methyl group.

[0033] R 5 R may be a linear, branched or cyclic alkyl group, and is preferably a linear alkyl group. 5 The number of carbon atoms in R is preferably 19 or more, and more preferably 20 or more. 5 is linear and R 5 The larger the carbon number of R, the better the effect of improving dispersibility. 5 may have a substituent, but is preferably an alkyl group that has no substituent (particularly, does not have a fluorine atom). 5 For example, -C 12 H 25 , -C 14 H 29 , -C 16 H 33 , -C 18 H 37 , -C 20 H 41 , -C 22 H 45 , -C 24 H 49 etc.

[0034] In one embodiment, polymer A comprises a third monomer unit and R 5 can be a linear alkyl group, preferably R 5 has 19 or more carbon atoms.

[0035] Q 3 The divalent linking group in is not particularly limited, and examples thereof include a carbonyl group, an ester bond, a urethane bond, an amide bond, etc. These linking groups may be of one type or a combination of two or more types.

[0036] Examples of the compound represented by formula (3) include lauryl methacrylate, tetradecyl methacrylate, hexadecyl methacrylate, stearyl methacrylate, behenyl methacrylate, icosyl methacrylate, phytanyl methacrylate, 2-tetradecyl octadecyl methacrylate, and 2-hexadecylic icosyl methacrylate.

[0037] 1-4. Other monomers In addition to the above-mentioned monomer units, the polymer A in the present invention may contain structural units derived from other monomers, as long as the effects of the present invention are not impaired.

[0038] The other monomer is not particularly limited, but examples thereof include various vinyl monomers such as styrene, t-butylstyrene, α-methylstyrene, vinyltoluene, acrylonitrile, methacrylonitrile, vinyl acetate, vinyl propionate, alkyl vinyl ether, hydroxyalkyl vinyl ether, alkyl vinyl monomer, etc. One type of other monomer may be used alone, or two or more types may be used.

[0039] 2. Production method of polymer A The method for producing a polymer in the present invention is not particularly limited, but may include, for example, a polymerization step.

[0040] In the polymerization step, raw material monomers including necessary monomers from among the first monomer, second monomer, third monomer, and other monomers are polymerized to obtain a homopolymer or copolymer. The polymerization method for the homopolymer or intermediate copolymer is not particularly limited, but known polymerization methods such as solution polymerization, suspension polymerization, and bulk polymerization can be used, with solution polymerization being preferred. Hexafluorometaxylene (HFMX) is preferred as the solvent for solution polymerization.

[0041] Furthermore, a polymerization initiator can be used in the polymerization reaction. The polymerization initiator is not particularly limited, and examples thereof include azo compounds such as azobisisobutyronitrile, azobis-2,4-dimethylvaleronitrile, azobis(4-methoxy-2,4-dimethylvaleronitrile), azobisdimethylvaleronitrile, and azobismethoxyvaleronitrile, peroxides such as acetyl peroxide, benzoyl peroxide, lauroyl peroxide, acetylcyclohexylsulfonyl peroxide, and 2,4,4-trimethylpentyl-2-peroxyphenoxyacetate, percarbonate compounds such as di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, and diethoxyethyl peroxydicarbonate, and perester compounds such as t-butyl peroxyneodecanate, α-cumyl peroxyneodecanate, and t-butyl peroxyneodecanate, which can be used alone or in combination.

[0042] The method for producing polymer A may further include a solvent removal step, in which the solvent can be removed by, for example, heat drying.

[0043] <Solubility in fluorinated solvents> The polymer A of the present invention can be dissolved in a fluorine-based solvent. The fluorine-based solvent is, for example, a fluorine-atom-containing hydrocarbon. The polymer A may be partially dissolved in the fluorine-based solvent or may be completely dissolved in the fluorine-based solvent. Preferably, the polymer A is completely dissolved in the fluorine-based solvent.

[0044] The fluorine-based solvent is not particularly limited as long as it contains one or more fluorine atoms and can be used as a solvent. The fluorine-based solvent contains fluorine and carbon, and may further contain chlorine, oxygen, and hydrogen. Examples of the fluorine-based solvent include hydrofluoroethers, hydrofluoroolefins, aromatic fluorine compounds, perfluorocarbons, and perfluoropolyethers.

[0045] Examples of hydrofluoroethers include perfluoroalkyl ethers such as 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, perfluoropropyl methyl ether, perfluorobutyl methyl ether, perfluorobutyl ethyl ether, and perfluoro-2-methylpentyl methyl ether.

[0046] Examples of hydrofluoroolefins include cis-1,1,1,4,4,4-hexafluoro-2-butene, 1-chloro-2,3,3-trifluoropropene, and trans-1,1,1,4,4,4-hexafluoro-2-butene.

[0047] Examples of aromatic fluorine compounds include hexafluorobenzene, hexafluorometaxylene, and octafluorotoluene.

[0048] Examples of perfluorocarbons include perfluoromethylcyclohexane, perfluoro-1,3-dimethylcyclohexane, perfluoropentene, perfluorohexene, and perfluorobenzene.

[0049] Examples of perfluoropolyethers include compounds containing one or more units selected from the group consisting of (CFCFCFO), (OCF(CF)CF), (OCFCF), and (OCF). Commercially available perfluoropolyethers include those under the trade names Demnum series (manufactured by Daikin Industries, Ltd.), Fomblin series and Galden series (manufactured by Solvay Specialty Polymers Japan), Barielta series (manufactured by NOK Kluber), and Krytox series (manufactured by Mitsui-DuPont Fluorochemicals Co., Ltd.).

[0050] 3.Resin composition The resin composition according to one embodiment of the present invention may contain the polymer A. The content of polymer A is preferably 80 to 100% by mass, more preferably 90 to 100% by mass, based on the total mass of the resin composition.

[0051] <Other ingredients> The resin composition of the present invention may contain other components as needed, provided that the object of the present invention is not impaired. The other components are not particularly limited and include, for example, polymers other than the polymer of the present invention, plasticizers, antioxidants, crosslinking agents, thickeners, solid lubricants, liquid lubricants, extreme pressure agents, oiliness agents, rust inhibitors, corrosion inhibitors, dyes, color stabilizers, viscosity index improvers, pour point depressants, structural stabilizers, antifoaming agents, conductive agents, light stabilizers, metal deactivators, and moisture absorbents.

[0052] Examples of the solid lubricant include fluororesin particles, molybdenum disulfide, melamine cyanurate, boron nitride, talc, organic bentonite, carbon black, graphene, etc. Examples of the liquid lubricant include silicone oil, polyalkylene glycol, polyol ester, diester, poly-α-olefin, alkyl diphenyl ether, and other chemically synthesized oils, mineral oil, etc.

[0053] The resin composition of the present invention may contain a solvent, preferably a fluorine-based solvent. The fluorine-based solvent is, for example, a fluorine-containing hydrocarbon. The above-mentioned solvents can be used as the fluorine-based solvent.

[0054] In one embodiment, the resin composition may be a lubricant composition. The lubricant composition may contain the polymer of the present invention, fluororesin particles, and a solvent such as a fluorine-based solvent. The lubricant composition may be a solvent-diluted lubricant composition that can be further diluted with a solvent before use.

[0055] In the lubricant composition, the content of the polymer A is preferably 0.0001 to 10 mass% relative to 100 mass% of the total mass of the lubricant composition, and is preferably 0.01 part by mass or more relative to 100 parts by mass of the fluororesin particles.

[0056] In the present invention, "fluororesin particles" refers to powdery resin particles containing fluorine, which have a molecular weight of 10,000 or more, or an average particle size of 50 μm or less. The fluororesin particles may have a molecular weight of 10,000 or more and an average particle size of 50 μm or less. The average particle size of the fluororesin particles may be, for example, 0.05 μm or more. While the polymer of the present invention has fluidity (is a waxy solid) and does not become powdery at room temperature and normal pressure (e.g., 20°C, 1 atm), the fluororesin particles of the present invention are in a powdery form at room temperature and normal pressure. The fluororesin particles are particles composed of a resin with a different composition from the polymer A, and preferably do not contain (meth)acrylate as a main constituent unit. The fluororesin particles preferably have a content of monomer units derived from (meth)acrylate as a constituent unit of less than 50% by mass, more preferably 5% by mass or less, and even more preferably 0% by mass. The fluororesin particles are not particularly limited, but examples thereof include polytetrafluoroethylene (PTFE), tetrafluoroethylene perfluorovinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-ethylene copolymer (ETFE), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), chlorotrifluoroethylene-ethylene copolymer (FCTFE), polychlorotrifluoroethylene (PCTFE), etc. PTFE is particularly suitable as a material to be dispersed by the dispersant according to the present invention.

[0057] 4. Dispersants The polymer A can be used as a dispersant for dispersing fluororesin particles in a solvent. A dispersant according to one embodiment of the present invention contains the polymer A (dispersant composition). The polymer A contained in the dispersant may be one type, or two or more types having different compositions may be used in combination.

[0058] <Other ingredients> The dispersant of the present invention may contain other components as additives as necessary, provided that the object of the present invention is not impaired. The other components are not particularly limited and include, for example, polymers other than the above-mentioned polymer A, plasticizers, antioxidants, crosslinking agents, thickeners, lubricants, extreme pressure agents, oiliness agents, rust inhibitors, corrosion inhibitors, dyes, color stabilizers, viscosity index improvers, pour point depressants, structural stabilizers, antifoaming agents, conductive agents, light stabilizers, metal deactivators, and moisture absorbents.

[0059] <How to prepare the dispersion liquid> The dispersion is obtained by stirring or applying ultrasonic waves to a mixture containing fluororesin particles, a fluorine-based solvent, the polymer A or a dispersant, and additives that can be used as needed. The dispersion contains, for example, preferably 0.01 to 10 parts by mass, more preferably 0.05 to 1 part by mass, of the polymer A per 100 parts by mass of the fluorine-based solvent.

[0060] <How to use the dispersion> The dispersion may be used, for example, by applying the dispersion to a substrate and drying it. The dried dispersion may be heated and baked. By such a method, a film containing fluororesin particles can be formed on the substrate. [Example]

[0061] EXAMPLES The present invention will be specifically explained below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0062] <Polymer synthesis> The abbreviations of the monomers shown in the synthesis examples are as follows. LMA: Lauryl methacrylate (CH2=CCH3-C(=O)-OC 12 H 25 ) TDMA: Tetradecyl methacrylate (CH2=CCH3-C(=O)-OC 14 H 29 ) HDMA: Hexadecyl methacrylate (CH2=CCH3-C(=O)-OC 16 H33 ) StMA: Stearyl methacrylate (CH2=CCH3-C(=O)-OC 18 H 37 ) BeMA: Behenyl methacrylate (CH2=CCH3-C(=O)-OC 22 H 45 ) ITDODA: 2-tetradecyl octadecyl acrylate (CH2=CCH3-C(=O)-O-CH2CH(C 14 H 29 )C 16 H 33 ) IHDIMA: 2-hexadecylicosyl methacrylate (CH2=CCH3-C(=O)-O-CH2CH(C 16 H 33 )C 18 H 37 ) C4FA: 2-(perfluorobutyl)ethyl acrylate (CH2=CH-C(=O)-O-CH2CH2-C4F9) C4FMA: Perfluorobutylethyl methacrylate (CH2=CCH3-C(=O)-O-CH2CH2-C4F9) C6FMA: Perfluorohexylethyl methacrylate (CH2=CCH3-C(=O)-O-CH2CH2-C6F 13 ) PO3MA:PFPE (HFPO trimer) methacrylate (CH2=CCH3-C(=O)-O-CH2-CF(CF3)O-CF2CF(CF3)O-CF2CF2CF3) PO6MA:PFPE (HFPO hexamer) methacrylate (CH2=CCH3-C(=O)-O-CH2-CF(CF3)O-(CF2CF(CF3)O)4-CF2CF2CF3) C10GA: Fluorinated triethylene glycol monobutyl ether acrylate (CH2=CH-C(=O)-O-CH2-CF2O-(CF2CF2O)2-CF2CF2CF2CF3) C10GMA: Fluorinated triethylene glycol monobutyl ether methacrylate (CH2=CCH3-C(=O)-O-CH2-CF2O-(CF2CF2O)2-CF2CF2CF2CF3) C10GUA: Fluorinated triethylene glycol monobutyl ether urethane ethyl acrylate (CH2=CH-C(=O)-O-CH2CH2-NH-C(=O)-O-CH2-CF2O-(CF2CF2O)2-CF2CF2CF2CF3) PO6-DE-MA:CH2=CCH3-C(=O)-O-CH2CH2-OC(=O)-CF(CF3)-(OCF2(CF3)CF)4-OCF2CF2CF3 <Measurement of weight average molecular weight of each polymer> The polymers of the examples and comparative examples were dissolved in tetrahydrofuran, and the weight average molecular weight of the eluted fraction was measured by gel permeation chromatography (GPC). The detected peaks were obtained as weight average molecular weights converted to polystyrene, and were measured under the conditions described below.

[0063] <Weight-average molecular weight measurement by gel permeation chromatography (GPC)> GPC measurement was carried out under the following conditions. The weight average molecular weight was calculated in terms of polystyrene. Gel permeation chromatography measuring device: Tosoh Corporation, HLC-8320 Column: Tosoh TSKgel GMHHR-M Eluent: tetrahydrofuran ·Eluent flow rate: 0.6ml / min Column temperature: 40℃ Detection method: Differential refractive index (RI) meter Calibration curve: Created using standard polystyrene

[0064] [Example 1] A reactor equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen inlet tube was charged with 100 parts by mass of POMA and 400 parts by mass of hexafluoromethane xylene (HFMX), followed by nitrogen substitution. Subsequently, 1 part by mass of azobisisobutyronitrile (AIBN, manufactured by Kanto Chemical Co., Ltd.) was added, and the mixture was reacted at 70°C for 8 hours to obtain a polymer solution.

[0065] [Examples 2 to 5] Synthesis was carried out in the same manner as in Example 1, except that the monomers shown in Table 1 were used. The amount of each monomer shown in Table 1 is in parts by mass.

[0066] [Example 6] A reactor equipped with a stirrer, reflux condenser, thermometer, and nitrogen inlet tube was charged with 80 parts by mass of PO3MA, 20 parts by mass of BeMA, and 400 parts by mass of HFMX, and nitrogen substitution was performed. Subsequently, 1 part by mass of initiator AIBN was added, and the reaction was carried out at 70°C for 8 hours to obtain a polymer solution. The weight-average molecular weight of the obtained polymer was 14,000.

[0067] [Example 6-2] The polymer was synthesized in the same manner as in Example 6, except that the amount of initiator was changed to 0.5 parts by mass. The weight-average molecular weight of the resulting polymer was 35,000. In the evaluation methods for the polymer described below, the solubility in HFMX was 3, the solubility in HFE was 3, and the dispersibility was 5.

[0068] [Example 6-3] The polymer was synthesized in the same manner as in Example 6, except that the amount of initiator was changed to 0.1 parts by mass. The weight-average molecular weight of the resulting polymer was 120,000. In the evaluation methods described below for the polymer, the solubility in HFMX was 3, the solubility in HFE was 2, and the dispersibility was 4.

[0069] [Examples 7 to 19] Synthesis was carried out in the same manner as in Example 6, except that the types of monomers shown in Table 1 were used in the mass ratios shown in Table 1.

[0070] [Example 20] A reactor equipped with a stirrer, reflux condenser, thermometer, and nitrogen inlet tube was charged with 60 parts by weight of PO3MA, 25 parts by weight of BeMA, 15 parts by weight of C4FMA, and 400 parts by weight of HFMX, and nitrogen substitution was performed. Subsequently, 1 part by weight of initiator AIBN was added, and the reaction was carried out at 70°C for 8 hours to obtain a polymer solution. The weight-average molecular weight of the obtained polymer was 15,000.

[0071] [Example 20-2] The polymer was synthesized in the same manner as in Example 20, except that the amount of initiator was changed to 0.5 parts by mass. The weight-average molecular weight of the resulting polymer was 25,000. In the evaluation methods for the polymer described below, the solubility in HFMX was 3, the solubility in HFE was 3, and the dispersibility was 5.

[0072] [Example 20-3] The polymer was synthesized in the same manner as in Example 20, except that the amount of initiator was changed to 0.1 parts by mass. The weight-average molecular weight of the resulting polymer was 100,000. In the evaluation methods described below for the polymer, the solubility in HFMX was 3, the solubility in HFE was 2, and the dispersibility was 4.

[0073] [Examples 21 to 24] Synthesis was performed in the same manner as in Example 20, except that the types of monomers shown in Table 1 were used in the mass ratios shown in Table 1.

[0074] [Comparative Examples 2 to 4, Comparative Example 7] Synthesis was carried out in the same manner as in Example 1, except that the monomers shown in Table 2 were used.

[0075] [Comparative Examples 5 to 6] Synthesis was carried out in the same manner as in Example 6, except that the types of monomers shown in Table 2 were used in the mass ratios shown in Table 1.

[0076] <Evaluation of solubility in fluorinated solvents> To the polymer solutions obtained in the Examples and Comparative Examples, each fluorine-based solvent (fluorine-based solvent 1 or fluorine-based solvent 2) was added so that the polymer was 0.1 parts by mass per 99.9 parts by mass of fluorine-based solvent. The resulting mixed solution was stirred with a magnetic stirrer (500 rpm) at 25°C for 1 hour, and then the presence or absence of precipitation of the polymer from the solution was visually confirmed. The solubility was evaluated using the following three-point scale. A score of 2 or higher was considered acceptable for practical use. The fluorine-based solvents used were hexafluorometaxylene (HFMX) [fluorine-based solvent 2] and hydrofluoroether (HFE, Novec 7100) [fluorine-based solvent 1]. 3: Polymer completely dissolved (no polymer precipitation) 2: Part of the polymer is dissolved (some precipitation of the polymer is observed, but the precipitate is stably dispersed in the solution) 1: The polymer is insoluble (most of the polymer is precipitated and no dissolution is observed, and the precipitate is either settling or floating in the solution)

[0077] <Preparation of dispersion liquid> The polymer solutions obtained in the examples and comparative examples were added to 99.9 parts by mass of hydrofluoroether (HFE, Novec 7100) so that the polymer solid content was 0.1 parts by mass, and the mixed solution was stirred with a magnetic stirrer (500 rpm) at 25°C for 1 hour, after which 1 part by mass of PTFE was added and treated with a homomixer to prepare evaluation samples. As the PTFE, Dyneon TF-9207Z manufactured by 3M Japan Ltd. was used.

[0078] <Dispersibility evaluation> The PTFE dispersion obtained by the above procedure was filled into a glass bottle and adjusted so that the liquid level was 6 cm. Next, the glass bottle was shaken 30 times and then allowed to stand. After 1 minute, the sedimentation state was visually checked and evaluated on the following 5-point scale. A score of 3 or higher was considered acceptable for practical use. 5: No clear phase separation 4: Less than 5% phase separation 3: Phase separation of 5% or more and less than 20% of the total 2: Phase separation of 20% or more but less than 50% of the total 1: Phase separation of 50% or more of the total

[0079] [Table 1]

[0080] [Table 2]

[0081] [Table 3]

[0082] From the results shown in Tables 1 to 3, when no dispersant was added in Comparative Example 1, the fluororesin particles did not disperse at all. The dispersant in Comparative Example 2 had excellent solubility in the fluorosolvent, but the dispersibility was not sufficient for practical use. The dispersants in Comparative Examples 3 and 7 did not dissolve at all in the fluorosolvent and precipitated, and the dispersibility was also poor. The dispersants in Comparative Examples 5 and 6 did not dissolve at all in the fluorosolvent and precipitated, and the dispersibility was also not sufficient for practical use. In contrast, it is clear that the dispersant of the present invention has excellent solubility and dispersibility in fluorine-containing solvents.

Claims

1. A dispersant for dispersing fluororesin particles in a fluorine solvent, comprising a polymer, the dispersant comprising: the polymer contains at least two structural units of a first monomer unit, a second monomer unit, and a third monomer unit, or is composed solely of the second monomer unit; The first monomer unit is a structural unit derived from a first monomer represented by the following formula (1): The second monomer unit is a structural unit derived from a second monomer represented by the following formula (2): The third monomer unit is a structural unit derived from a third monomer represented by the following formula (3): Dispersant. CH ２ =CR １ -COO-Q １ -Rf １ (1) R １ : a hydrogen atom or a methyl group, Rf １ : a polyfluoroalkyl group having 1 to 4 carbon atoms, Q １ A divalent linking group selected from -CH 2 -, -CH 2 CH 2 -, -CH 2 CH 2 CH 2 -, and -CH 2 CH 2 CH 2 CH 2 -. CH ２ =CR ２ -COO-R ３ -Q ２ -Rf ２ (2) R ２ : a hydrogen atom or a methyl group, R ３ : an alkylene group having 1 to 6 carbon atoms, Rf ２ : a perfluoropolyether group having 5 to 20 carbon atoms, Q ２ : a single bond, or -NH-COO-Q ２１ - and Q ２１ is a linking group which is a single bond or an alkylene group. CH ２ =CR ４ -COO-Q ３ -R ５ (3) R ４ : a hydrogen atom or a methyl group, R ５ : an alkyl group having 12 to 40 carbon atoms, Q ３ : A single bond or a divalent linking group.

2. A dispersant as described in claim 1, wherein the polymer comprises the second monomer unit and the third monomer unit.

3. A dispersant as described in claim 1, wherein the polymer comprises the first monomer unit, the second monomer unit, and the third monomer unit.

4. The polymer comprises the third monomer unit, and in the formula (3), R ５ The dispersant according to claim 1, wherein the number of carbon atoms is 19 or more.

5. The polymer comprises the third monomer unit, and in the formula (3), R ５ 2. The dispersant of claim 1, wherein the carbon chain of

6. The polymer comprises the second monomer unit, and Rf in formula (2) ２ The dispersant according to claim 1, wherein is a perfluoropolyether having 8 to 20 carbon atoms.

7. The dispersant described in claim 1, wherein the polymer contains the second monomer unit and the perfluoropolyether group in formula (2) is represented by the following formula (4): F(CF ２ CF ２ O) ｂ (CF(CF ３ )CF ２ O) ｃ (CF ２ O) ｄ (CF ２ CF ２ CF ２ O) ｅ (CF ２ CF ２ CF ２ CF ２ O) f ・・・(4) In the formula (4), b, c, d, e, and f each independently represent 0 or an integer of 1 or more, and b+c+d+e+f is 2 to 20; (CF ２ CF ２ O), (CF (CF ３ )CF ２ O), (CF ２ O), (CF ２ CF ２ CF ２ O), (CF ２ CF ２ CF ２ CF ２ The bonding order of the repeating units of (O) is not limited, and they may be bonded to each other randomly or in blocks.

8. The dispersant of claim 1, wherein the polymer is soluble in a fluorine-containing solvent.

9. 9. The dispersant according to claim 8, wherein the fluorine-based solvent is any one selected from the group consisting of hydrofluoroethers, hydrofluoroolefins, aromatic fluorine compounds, perfluorocarbons, and perfluoropolyethers.

10. A lubricant composition comprising a polymer, a fluorine-based solvent, and fluororesin particles, the polymer contains at least two structural units of a first monomer unit, a second monomer unit, and a third monomer unit, or is composed solely of the second monomer unit; The first monomer unit is a structural unit derived from a first monomer represented by the following formula (1): The second monomer unit is a structural unit derived from a second monomer represented by the following formula (2): The lubricant composition, wherein the third monomer unit is a structural unit derived from a third monomer represented by the following formula (3): CH 2 =CR 1 -COO-Q 1 -Rf 1 (1) R 1 : a hydrogen atom or a methyl group, Rf 1 : a polyfluoroalkyl group having 1 to 4 carbon atoms Q 1 : a divalent linking group selected from -CH 2 -, -CH 2 CH 2 -, -CH 2 CH 2 CH 2 -, and -CH 2 CH 2 CH 2 CH 2 -. CH 2 =CR 2 -COO-R 3 -Q 2 -Rf 2 (2) R 2 : a hydrogen atom or a methyl group, R 3 : an alkylene group having 1 to 6 carbon atoms, Rf 2 : a perfluoropolyether group having 5 to 20 carbon atoms, Q 2 : a single bond or a linking group represented by -NH-COO-Q 21 -, where Q 21 is a single bond or an alkylene group. CH 2 =CR 4 -COO-Q 3 -R 5 (3) R 4 : a hydrogen atom or a methyl group, R 5 : an alkyl group having 12 to 40 carbon atoms; Q 3 : A single bond or a divalent linking group.

Images