Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F2/00—Processes of polymerisation
  • C08F2/12—Polymerisation in non-solvents
  • C08F2/16—Aqueous medium
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F214/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen
  • C08F214/18—Monomers containing fluorine
  • C08F214/22—Vinylidene fluoride
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F14/00—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen
  • C08F14/18—Monomers containing fluorine
  • C08F14/22—Vinylidene fluoride
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F2/00—Processes of polymerisation
  • C08F2/12—Polymerisation in non-solvents
  • C08F2/16—Aqueous medium
  • C08F2/18—Suspension polymerisation
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F2/00—Processes of polymerisation
  • C08F2/12—Polymerisation in non-solvents
  • C08F2/16—Aqueous medium
  • C08F2/22—Emulsion polymerisation
  • C08F2/24—Emulsion polymerisation with the aid of emulsifying agents
  • C08F2/26—Emulsion polymerisation with the aid of emulsifying agents anionic
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F2800/00—Copolymer characterised by the proportions of the comonomers expressed
  • C08F2800/10—Copolymer characterised by the proportions of the comonomers expressed as molar percentages

Definitions

• the present disclosure relates to a method for producing a fluorine-containing elastomer aqueous dispersion.
• Patent Document 1 discloses emulsification using a reactive surfactant composed of a compound having a radically polymerizable unsaturated bond and a hydrophilic group in the molecule as a surfactant. Polymerization is described.
• the object is to provide a manufacturing method that can be advanced.
• a fluorine-containing elastomer aqueous dispersion is produced by polymerizing a fluorine-containing monomer in the presence of an aqueous medium and a fluorine-containing compound (A) to produce an aqueous dispersion containing a fluorine-containing elastomer.
• the fluorine-containing elastomer contains a methylene group in its main chain
• a manufacturing method is provided.
• the hydrophilic group is -NH 2 , -P(O)(OM) 2 , -OP(O)(OM) 2 , -SO 3 M, -OSO 3 M or -COOM (in each formula, M is H , a metal atom, NR 74 , optionally substituted imidazolium, optionally substituted pyridinium or optionally substituted phosphonium, R 7 is H or an organic group and may be the same or different, any two of which may be bonded to each other to form a ring).
• the fluorine-containing elastomer preferably contains vinylidene fluoride units.
• the fluorine-containing elastomer contains vinylidene fluoride units in an amount of 50 mol % or more based on all monomer units. It is preferable to supply the fluorine-containing compound (A) even before starting the polymerization of the fluorine-containing monomer.
• the amount of the fluorine-containing compound (A) supplied after starting the polymerization of the fluorine-containing monomer is preferably 30 to 300 mass ppm with respect to the aqueous medium. It is preferable to polymerize the fluoromonomer in the absence of a fluorosurfactant substantially free of radically polymerizable unsaturated bonds.
• the Mooney viscosity (ML1+10 (100° C.)) of the fluorine-containing elastomer is preferably 10-130.
• the polymerization of the fluoromonomer can be performed while suppressing the adhesion of the fluoroelastomer to the polymerization tank without using a relatively large amount of reactive surfactant as in conventional production methods. It is possible to provide a manufacturing method that can proceed smoothly.
• the fluorine-containing elastomer is an amorphous fluoropolymer.
• “Amorphous” means a melting peak ( ⁇ H ) is 4.5 J/g or less.
• Fluorine-containing elastomers exhibit elastomeric properties by cross-linking. By elastomeric properties is meant the property of being able to stretch a polymer and retain its original length when the force required to stretch the polymer is no longer applied.
• a perfluoromonomer is a monomer that does not contain a carbon atom-hydrogen atom bond in its molecule.
• the perfluoromonomer may be a monomer in which some of the fluorine atoms bonded to the carbon atoms are substituted with chlorine atoms in addition to carbon atoms and fluorine atoms, and in addition to carbon atoms, nitrogen atoms, oxygen atoms, sulfur atoms, phosphorus atoms, boron atoms or silicon atoms.
• the above perfluoromonomer is preferably a monomer in which all hydrogen atoms are substituted with fluorine atoms.
• the above perfluoromonomers do not include monomers that provide crosslinkable groups.
• a monomer that provides a cross-linking site is a monomer (cure site monomer) that provides the fluoropolymer with a cross-linking site for forming cross-links with a curing agent.
• a monomer that provides a cross-linking site includes a monomer that provides a cross-linkable group.
• each monomer unit constituting the fluorine-containing elastomer can be calculated by appropriately combining NMR, FT-IR, elemental analysis, and fluorescent X-ray analysis depending on the type of monomer.
• organic group means a group containing one or more carbon atoms or a group formed by removing one hydrogen atom from an organic compound.
• organic groups are an alkyl group optionally having one or more substituents, an alkenyl group optionally having one or more substituents, an alkynyl group optionally having one or more substituents, a cycloalkyl group optionally having one or more substituents, a cycloalkenyl group optionally having one or more substituents, a cycloalkadienyl group optionally having one or more substituents, an aryl group optionally having one or more substituents, an aralkyl group optionally having one or more substituents, a non-aromatic heterocyclic group optionally having one or more substituents, a heteroaryl group optionally having one or more substituents, cyano group, formyl group, RaO-, RaCO-, RaSO2- , RaCOO-, Ra
• substituteduent means a substitutable group.
• substitutable group examples include an aliphatic group, an aromatic group, a heterocyclic group, an acyl group, an acyloxy group, an acylamino group, an aliphatic oxy group, an aromatic oxy group, a heterocyclic oxy group, an aliphatic oxycarbonyl group , aromatic oxycarbonyl group, heterocyclic oxycarbonyl group, carbamoyl group, aliphatic sulfonyl group, aromatic sulfonyl group, heterocyclic sulfonyl group, aliphatic sulfonyloxy group, aromatic sulfonyloxy group, heterocyclic sulfonyloxy group, sulfamoyl group, aliphatic sulfonamide group, aromatic sulfonamide group, heterocyclic sulfonamide group, amino group, aliphatic sulfonamide group, aromatic sulf
• the above aliphatic group may be saturated or unsaturated, and may be a hydroxy group, an aliphatic oxy group, a carbamoyl group, an aliphatic oxycarbonyl group, an aliphatic thio group, an amino group, an aliphatic amino group. , an acylamino group, a carbamoylamino group, and the like.
• the aliphatic group include alkyl groups having a total carbon number of 1 to 8, preferably 1 to 4, such as methyl, ethyl, vinyl, cyclohexyl and carbamoylmethyl groups.
• the aromatic group includes, for example, a nitro group, a halogen atom, an aliphatic oxy group, a carbamoyl group, an aliphatic oxycarbonyl group, an aliphatic thio group, an amino group, an aliphatic amino group, an acylamino group, a carbamoylamino group, and the like.
• You may have The aromatic group includes an aryl group having 6 to 12 carbon atoms, preferably 6 to 10 carbon atoms in total, such as a phenyl group, a 4-nitrophenyl group, a 4-acetylaminophenyl group and a 4-methanesulfonylphenyl group. etc.
• the heterocyclic group has a halogen atom, a hydroxy group, an aliphatic oxy group, a carbamoyl group, an aliphatic oxycarbonyl group, an aliphatic thio group, an amino group, an aliphatic amino group, an acylamino group, a carbamoylamino group, and the like.
• the heterocyclic group include 5- to 6-membered heterocyclic rings having a total carbon number of 2 to 12, preferably 2 to 10, such as 2-tetrahydrofuryl group and 2-pyrimidyl group.
• the acyl group includes an aliphatic carbonyl group, an arylcarbonyl group, a heterocyclic carbonyl group, a hydroxy group, a halogen atom, an aromatic group, an aliphatic oxy group, a carbamoyl group, an aliphatic oxycarbonyl group, an aliphatic thio group, and an amino group. , an aliphatic amino group, an acylamino group, a carbamoylamino group, and the like.
• the acyl group includes acyl groups having 2 to 8, preferably 2 to 4 carbon atoms in total, such as acetyl, propanoyl, benzoyl and 3-pyridinecarbonyl groups.
• the acylamino group may have an aliphatic group, an aromatic group, a heterocyclic group, and the like, and has, for example, an acetylamino group, a benzoylamino group, a 2-pyridinecarbonylamino group, a propanoylamino group, and the like.
• the acylamino group include acylamino groups having a total number of carbon atoms of 2 to 12, preferably 2 to 8, and alkylcarbonylamino groups having a total number of carbon atoms of 2 to 8, such as acetylamino, benzoylamino and 2-pyridinecarbonylamino. groups, propanoylamino groups, and the like.
• the aliphatic oxycarbonyl group may be saturated or unsaturated, and may be a hydroxy group, an aliphatic oxy group, a carbamoyl group, an aliphatic oxycarbonyl group, an aliphatic thio group, an amino group, an aliphatic It may have an amino group, an acylamino group, a carbamoylamino group, or the like.
• Examples of the aliphatic oxycarbonyl group include alkoxycarbonyl groups having 2 to 8, preferably 2 to 4 carbon atoms in total, such as methoxycarbonyl, ethoxycarbonyl and (t)-butoxycarbonyl groups.
• the carbamoyl group may have an aliphatic group, an aromatic group, a heterocyclic group, and the like.
• Examples of the carbamoyl group include an unsubstituted carbamoyl group, an alkylcarbamoyl group having a total of 2 to 9 carbon atoms, preferably an unsubstituted carbamoyl group, an alkylcarbamoyl group having a total of 2 to 5 carbon atoms, such as an N-methylcarbamoyl group, N,N-dimethylcarbamoyl group, N-phenylcarbamoyl group and the like.
• the aliphatic sulfonyl group may be saturated or unsaturated, and may be a hydroxy group, an aromatic group, an aliphatic oxy group, a carbamoyl group, an aliphatic oxycarbonyl group, an aliphatic thio group, an amino group. , an aliphatic amino group, an acylamino group, a carbamoylamino group, and the like.
• Examples of the aliphatic sulfonyl groups include alkylsulfonyl groups having 1 to 6 total carbon atoms, preferably 1 to 4 total carbon atoms, such as methanesulfonyl groups.
• the aromatic sulfonyl group includes a hydroxy group, an aliphatic group, an aliphatic oxy group, a carbamoyl group, an aliphatic oxycarbonyl group, an aliphatic thio group, an amino group, an aliphatic amino group, an acylamino group, a carbamoylamino group, and the like. You may have Examples of the aromatic sulfonyl group include arylsulfonyl groups having 6 to 10 carbon atoms in total, such as benzenesulfonyl groups.
• the above amino group may have an aliphatic group, an aromatic group, a heterocyclic group, or the like.
• the acylamino group may have, for example, an acetylamino group, a benzoylamino group, a 2-pyridinecarbonylamino group, a propanoylamino group, and the like.
• the acylamino group includes acylamino groups having 2 to 12 total carbon atoms, preferably 2 to 8 carbon atoms, more preferably alkylcarbonylamino groups having 2 to 8 total carbon atoms, such as acetylamino and benzoylamino. group, 2-pyridinecarbonylamino group, propanoylamino group and the like.
• the aliphatic sulfonamide group, aromatic sulfonamide group, and heterocyclic sulfonamide group may be, for example, a methanesulfonamide group, a benzenesulfonamide group, a 2-pyridinesulfonamide group, and the like.
• the above sulfamoyl group may have an aliphatic group, an aromatic group, a heterocyclic group, and the like.
• the sulfamoyl group include a sulfamoyl group, an alkylsulfamoyl group having a total number of carbon atoms of 1 to 9, a dialkylsulfamoyl group having a total number of carbon atoms of 2 to 10, and an arylsulfamoyl group having a total number of carbon atoms of 7 to 13.
• a heterocyclic sulfamoyl group having a total of 2 to 12 carbon atoms more preferably a sulfamoyl group, an alkylsulfamoyl group having a total of 1 to 7 carbon atoms, a dialkylsulfamoyl group having a total of 3 to 6 carbon atoms, a total carbon arylsulfamoyl group having 6 to 11 atoms, heterocyclic sulfamoyl group having 2 to 10 total carbon atoms, such as sulfamoyl group, methylsulfamoyl group, N,N-dimethylsulfamoyl group, phenylsulfamoyl group; group, 4-pyridinesulfamoyl group, and the like.
• the aliphatic oxy group may be saturated or unsaturated, and may have a methoxy group, ethoxy group, i-propyloxy group, cyclohexyloxy group, methoxyethoxy group, and the like.
• Examples of the aliphatic oxy group include alkoxy groups having a total carbon number of 1 to 8, preferably 1 to 6, such as methoxy, ethoxy, i-propyloxy, cyclohexyloxy and methoxyethoxy.
• the above aromatic amino group and heterocyclic amino group are an aliphatic group, an aliphatic oxy group, a halogen atom, a carbamoyl group, a heterocyclic group condensed with the aryl group, an aliphatic oxycarbonyl group, preferably the total number of carbon atoms 1 to 4 aliphatic groups, 1 to 4 total carbon atom aliphatic oxy groups, halogen atoms, 1 to 4 total carbon atom carbamoyl groups, nitro groups, 2 to 4 total carbon atom aliphatic oxycarbonyls You may have a group.
• the aliphatic thio group may be saturated or unsaturated, and an alkylthio group having 1 to 8 total carbon atoms, more preferably 1 to 6 total carbon atoms, such as a methylthio group and an ethylthio group. , carbamoylmethylthio group, t-butylthio group and the like.
• the carbamoylamino group may have an aliphatic group, an aryl group, a heterocyclic group, and the like.
• Examples of the carbamoylamino group include a carbamoylamino group, an alkylcarbamoylamino group having 2 to 9 total carbon atoms, a dialkylcarbamoylamino group having 3 to 10 total carbon atoms, an arylcarbamoylamino group having 7 to 13 total carbon atoms, heterocyclic carbamoylamino group having 3 to 12 total carbon atoms, preferably carbamoylamino group, alkylcarbamoylamino group having 2 to 7 total carbon atoms, dialkylcarbamoylamino group having 3 to 6 total carbon atoms, 7-11 arylcarbamoylamino groups, heterocyclic carbamoylamino groups having 3-10 total carbon atoms, such as carbamoylamino, methylcar
• ranges represented by endpoints include all numbers subsumed within that range (eg, 1 to 10 includes 1.4, 1.9, 2.33, 5.75, 9 .98, etc.).
• reference to "at least 1" includes all numbers greater than or equal to 1 (eg, at least 2, at least 4, at least 6, at least 8, at least 10, at least 25, at least 50, at least 100, etc.) .
• the polymerization of the fluoromonomer is initiated when the aqueous dispersion containing the fluoroelastomer is produced by polymerizing the fluoromonomer in the presence of an aqueous medium. After that, the fluorine-containing compound (A) represented by the general formula (A) is supplied to the polymerization system.
• the fluorine-containing compound (A) used in the production method of the present disclosure has a structure in which the number of carbon atoms in the portion other than the hydrophilic group (Y 3 ) is 6 or less, and the portion corresponding to the hydrophobic group in the molecule has a short chain. Characteristic. If the number of carbon atoms in the portion other than the hydrophilic group (Y 3 ) exceeds 6, it becomes necessary to use a relatively large amount of the compound in order to suppress adhesion of the fluorine-containing elastomer to the polymerization tank, which is economically disadvantageous. In addition, it is disadvantageous in that post-processing becomes complicated.
• the number of carbon atoms in the portion other than the hydrophilic group (Y 3 ) of the fluorine-containing compound (A) is such that the polymerization of the fluorine-containing monomer proceeds more smoothly while further suppressing adhesion of the fluorine-containing elastomer to the polymerization tank. is preferably 3 or more, more preferably 4 or more, and even more preferably 5 or more.
• the hydrophilic group (Y 3 ) of the fluorine-containing compound (A) may be a group exhibiting hydrophilicity, and may be an anionic hydrophilic group, a cationic hydrophilic group or a nonionic hydrophilic group, preferably anionic. It is a hydrophilic group.
• hydrophilic group (Y 3 ) in the fluorine-containing compound (A) examples include —NH 2 , —P(O)(OM) 2 , —OP(O)(OM) 2 , —SO 3 M, —OSO 3 M, —COOM (in each formula, M is H, a metal atom, NR 74 , imidazolium optionally having substituents, pyridinium optionally having substituents, or R 7 is H or an organic group, which may be the same or different, any two of which may combine with each other to form a ring.
• --SO 3 M or --COOM is preferable, and --COOM is more preferable.
• R 7 is preferably H or a C 1-10 organic group, more preferably H or a C 1-4 organic group, still more preferably H or a C 1-4 alkyl group, and most preferably H.
• the metal atom includes a monovalent or divalent metal atom, preferably an alkali metal (group 1) or an alkaline earth metal (group 2), more preferably Na, K or Li.
• R a in general formula (A) is a linking group.
• linking group refers to a divalent linking group.
• the linking group is preferably a single bond or a group containing at least one carbon atom.
• the number of carbon atoms in the linking group is selected so that the number of carbon atoms in the portion of the fluorine-containing compound (A) excluding the hydrophilic group is 6 or less.
• Linking groups may be linear or branched, cyclic or acyclic structures, saturated or unsaturated, substituted or unsubstituted, and optionally one or more selected from the group consisting of sulfur, oxygen, and nitrogen. It contains heteroatoms and may optionally contain one or more functional groups selected from the group consisting of ester, amide, sulfonamide, carbonyl, carbonate, urethane, urea and carbamate. Linking groups do not contain carbon atoms and may be catenary heteroatoms such as oxygen, sulfur or nitrogen.
• R a is preferably, for example, a catenary heteroatom such as oxygen, sulfur or nitrogen, or a divalent organic group.
• R a is a divalent organic group
• hydrogen atoms bonded to carbon atoms may be replaced by halogens other than fluorine, such as chlorine, and may or may not contain double bonds.
• R a may be chain or branched, and may be cyclic or non-cyclic.
• R a may also contain functional groups (eg, esters, ethers, ketones, amines, halides, etc.).
• R a may also be a non-fluorine divalent organic group or a partially fluorinated or perfluorinated divalent organic group.
• R a includes, for example, a hydrocarbon group in which fluorine atoms are not bonded to carbon atoms, a hydrocarbon group in which some of the hydrogen atoms bonded to carbon atoms are substituted with fluorine atoms, and hydrogen atoms bonded to carbon atoms
• R a is preferably a fluorinated alkylene group or a fluorinated oxyalkylene group. They are preferably linear. These carbon numbers are selected so that the number of carbon atoms in the portion excluding the hydrophilic group of the fluorine-containing compound (A) is 6 or less.
• the method of supplying the fluorine-containing compound (A) is not particularly limited. can be supplied For example, when the fluorine-containing monomer is continuously or intermittently supplied to the polymerization system, the fluorine-containing compound (A) is added to the fluorine-containing You may supply intermittently until the supply amount of a monomer reaches arbitrary points.
• the supply timing of the fluorine-containing compound (A) is not particularly limited as long as it is after the initiation of polymerization.
• a suitable supply point in the case of collectively supplying the fluorine-containing compound (A), or continuously supplying the fluorine-containing compound (A) Alternatively, a suitable supply timing in the case of intermittent supply is exemplified below.
• the fluorine-containing compound (A) When the fluorine-containing compound (A) is supplied all at once after the initiation of polymerization, the total amount (g) of the fluorine-containing monomers supplied after the initiation of polymerization is It is preferable to supply the fluorine-containing compound (A) after the supply amount (g) of reaches 5%. Moreover, it is preferable to supply the fluorine-containing compound (A) after the amount of the fluorine-containing monomer supplied after the initiation of polymerization reaches 10%, 20%, 30% or 40%.
• the total supply amount (g) of the fluorine-containing monomers supplied after the initiation of polymerization is It is preferable to supply the fluorine-containing compound (A) until the amount (g) of the monomer supplied reaches 90%. Moreover, it is preferable to supply the fluorine-containing compound (A) until the amount of the fluorine-containing monomer supplied after the initiation of polymerization reaches 85%, 80%, 75%, or 70%.
• the adhesion of the fluorine-containing elastomer to the polymerization tank can be further suppressed. It is preferable to start supplying the fluorine-containing compound (A) after the supply amount (g) of the fluorine-containing monomer supplied after the initiation of polymerization reaches 5%. Further, it is preferable to start supplying the fluorine-containing compound (A) after the amount of the fluorine-containing monomer supplied after the initiation of polymerization reaches 10%, 20%, 30% or 40%.
• the fluorine-containing compound (A) when the fluorine-containing compound (A) is supplied continuously or intermittently, the adhesion of the fluorine-containing elastomer to the polymerization tank can be further suppressed, so the total supply amount (g ), the supply of the fluorine-containing compound (A) is preferably stopped before the amount (g) of the fluorine-containing monomer supplied after the initiation of polymerization reaches 90%. Moreover, it is preferable to stop the supply of the fluorine-containing compound (A) before the amount of the fluorine-containing monomer supplied after the initiation of polymerization reaches 85%, 80%, 75%, or 70%.
• the fluorine-containing compound (A) may be supplied immediately after the polymerization is initiated, and the fluorine-containing compound (A) may be further supplied after the polymerization reaction has progressed for a certain period of time.
• the fluorine-containing monomer is continuously or intermittently supplied to the polymerization system, the fluorine-containing compound (A) is supplied immediately after the polymerization is started, and after a certain amount of the fluorine-containing monomer is supplied, A fluorine-containing compound (A) may be further supplied.
• immediateately after the initiation of polymerization means, for example, when the fluoromonomer is continuously or intermittently supplied to the polymerization system, the total supply amount of the fluoromonomer supplied after the initiation of polymerization ( This is the period before the amount (g) of the fluorine-containing monomer supplied after the initiation of polymerization reaches 1% of g).
• the supply point or timing of the supply of the fluorine-containing compound (A) is It can be a suitable supply time when the fluorine-containing compound (A) exemplified above is supplied all at once, or a suitable supply time when the fluorine-containing compound (A) is supplied continuously or intermittently. can.
• the point at which the polymerization reaction of the fluoromonomers is initiated usually refers to the addition of the polymerization initiator to the polymerization system. is added, and when the polymerization initiator is added to the polymerization system continuously or intermittently, it is the time when the polymerization initiator is first added to the polymerization system.
• the term "after initiation of polymerization” means the polymerization period from when the polymerization initiator is first added to the polymerization system to when the polymerization reaction of the fluorine-containing monomer is completed.
• "before initiation of polymerization” means the time when the polymerization initiator is first added to the polymerization system and the period prior to that time.
• the supply amount of the fluorine-containing compound (A) supplied after the polymerization of the fluorine-containing monomer is initiated is preferably 30 to 5000 ppm by mass, more preferably 80 ppm by mass or more, with respect to the aqueous medium. It is preferably 130 mass ppm or more, particularly preferably 150 mass ppm or more, most preferably 180 mass ppm or more, more preferably 1000 mass ppm or less, and still more preferably 500 mass ppm or less. , particularly preferably 450 mass ppm or less.
• the supply amount of the fluorine-containing compound (A) to be supplied after the polymerization of the fluorine-containing monomer is within the above range, the adhesion of the fluorine-containing elastomer to the polymerization tank is further suppressed while the fluorine-containing monomer is can proceed more smoothly.
• the supply amount of the fluorine-containing compound (A) supplied after the polymerization of the fluorine-containing monomer is initiated may be 300 mass ppm or less, or may be 250 mass ppm or less. It may be 200 ppm by mass or less. Since the production method of the present disclosure uses a fluorine-containing compound (A) having a specific structure, even if the supply amount of the fluorine-containing compound (A) is extremely small as described above, While suppressing adhesion of the fluoroelastomer, the polymerization of the fluoromonomer can proceed smoothly.
• the supply amount of the fluorine-containing compound (A) supplied after the initiation of polymerization refers to the amount supplied to the polymerization system after the initiation of the polymerization of the fluorine-containing monomer and before the completion of the polymerization reaction of the fluorine-containing monomer. is the supply amount of the fluorine-containing compound (A), and does not include the supply amount of the fluorine-containing compound (A) supplied to the polymerization system at the time and before the polymerization reaction of the fluorine-containing monomer is initiated.
• the fluorine-containing compound (A) is supplied after the polymerization of the fluorine-containing monomer is initiated, but the fluorine-containing compound (A) may also be supplied before the polymerization of the fluorine-containing monomer is initiated. is preferred.
• the fluorine-containing compound (A) before the initiation of the polymerization of the fluorine-containing monomer, the number of fluorine-containing elastomer particles generated by polymerization can be increased, and the polymerization of the fluorine-containing monomer can be further enhanced. It can proceed smoothly.
• the supply amount of the fluorine-containing compound (A) supplied before the polymerization of the fluorine-containing monomer is initiated is preferably 5 to 5000 ppm by mass, more preferably 10 ppm by mass or more, relative to the aqueous medium, It is more preferably 15 mass ppm or more, more preferably 1000 mass ppm or less, still more preferably 500 mass ppm or less, particularly preferably 300 mass ppm or less, and most preferably 200 mass ppm or less.
• the supply amount of the fluorine-containing compound (A) supplied before starting the polymerization of the fluorine-containing monomer may be 150 mass ppm or less, or 100 mass ppm or less. may be 70 ppm by mass or less. Since the production method of the present disclosure uses a fluorine-containing compound (A) having a specific structure, even if the amount of the fluorine-containing compound (A) supplied before the start of polymerization is extremely small, A sufficient number of fluorine-containing elastomer particles can be generated, and the polymerization of the fluorine-containing monomer can proceed smoothly.
• the total supply amount of the compound (A) is preferably 30 to 5000 ppm by mass, more preferably 100 ppm by mass or more, still more preferably 150 ppm by mass or more, particularly preferably 150 ppm by mass or more, relative to the aqueous medium.
• the total supply amount of the fluorine-containing compound (A) is 200 mass ppm or more, most preferably 250 mass ppm or more, more preferably 1000 mass ppm or less, and still more preferably 500 mass ppm or less.
• the amount of the fluorine-containing compound (A) supplied before the polymerization of the fluorine-containing monomer and the fluorine-containing monomer may be 450 mass ppm or less, may be 400 mass ppm or less, or may be 350 mass ppm or less. , 300 mass ppm or less, or 250 mass ppm or less.
• the production method of the present disclosure uses a fluorine-containing compound (A) having a specific structure, even if the total supply amount of the fluorine-containing compound (A) is extremely small, A sufficient number of fluoroelastomer particles can be generated at a sufficient polymerization rate while suppressing adhesion of the fluoroelastomer, and the polymerization of the fluoromonomer can proceed smoothly.
• the supply amount (a) of the fluorine-containing compound (A) supplied before the initiation of polymerization and the supply amount of the fluorine-containing compound (A) supplied after the initiation of polymerization is preferably 1/20 to 2/1, more preferably 1/10 to 1/1, still more preferably 1/10 ⁇ 7/10.
• a method of supplying the fluorine-containing compound (A) includes, for example, a method of supplying the fluorine-containing compound (A) from a pipe connected to the polymerization tank using a pump.
• the feed rate of the fluorine-containing compound (A) may be constant or may be changed.
• the polymerization of the fluorine-containing monomer is performed, for example, by charging an aqueous medium into a pressure-resistant polymerization tank equipped with a stirrer, removing oxygen, charging the monomer, bringing the temperature to a predetermined temperature, and starting the polymerization. It can be carried out by adding an agent to initiate polymerization, and after the initiation of polymerization, supplying the fluorine-containing compound (A) to the polymerization tank.
• the fluorine-containing compound (A) may be supplied to the polymerization tank after the polymerization is started, and the fluorine-containing compound (A) may be supplied to the polymerization tank before the polymerization is started.
• polymerization may be performed in the presence of a polymerization initiator.
• the polymerization initiator includes a radical polymerization initiator.
• the polymerization initiator is not particularly limited as long as it can generate radicals at the temperature at which the fluorine-containing monomer is polymerized, and oil-soluble polymerization initiators, water-soluble polymerization initiators, and the like can be used. , water-soluble polymerization initiators are preferred. Also, the polymerization initiator may be used in combination with a reducing agent or the like as a redox initiator.
• the amount of the polymerization initiator when polymerizing the fluorine-containing monomer is appropriately determined according to the type of monomer, the molecular weight of the target fluorine-containing elastomer, and the reaction rate.
• the amount of the polymerization initiator is appropriately determined depending on the molecular weight of the target fluorine-containing elastomer and the polymerization reaction rate, but is preferably 0.00001 to 10% by mass with respect to 100% by mass of the total amount of monomers. More preferably, it is 0.0001 to 1% by mass.
• an oil-soluble radical polymerization initiator a water-soluble radical polymerization initiator, or an azo compound can be used.
• Oil-soluble radical polymerization initiators may be known oil-soluble peroxides such as dialkylperoxycarbonates such as diisopropylperoxydicarbonate and disec-butylperoxydicarbonate; peroxy esters such as isobutyrate and t-butyl peroxypivalate; dialkyl peroxides such as di-t-butyl peroxide; ( ⁇ -hydro-tetradecafluorooctanoyl) peroxide, di( ⁇ -hydro-hexadecafluorononanoyl) peroxide, di(perfluorobutyryl) peroxide, di(perfluorovaleryl) peroxide, di (perfluorohexanoyl) peroxide, di (perfluoroheptanoyl) peroxide, di (perfluorooctanoyl) peroxide, di (perfluorononanoyl) peroxide, di ( ⁇ -chloro-he
• Azo compounds include azodicarboxylate, azodicarboxyldiamide, 2,2'-azobisisobutyronitrile, 2,2'-azobis 2,4-dimethylvaleronitrile, 2,2'-azobis ( 2-methylpropionamidine) dihydrochloride, 4,4′-azobis(4-cyanovaleric acid).
• the water-soluble radical polymerization initiator may be a known water-soluble peroxide, for example, persulfuric acid, perboric acid, perchloric acid, perphosphoric acid, ammonium salts such as percarbonic acid, potassium salts, sodium salts , disuccinic acid peroxide, diglutaric acid peroxide, t-butyl permaleate, t-butyl hydroperoxide and the like.
• a reducing agent such as sulfites may also be included, and the amount used may be 0.1 to 20 times that of the peroxide.
• a salt of persulfate is preferable because it is easy to adjust the amount of generated radicals, and potassium persulfate (K 2 S 2 O 8 ), ammonium persulfate ((NH 4 ) 2 S 2 O 8 ), preferably sodium persulfate (Na 2 S 2 O 8 ), most preferably ammonium persulfate.
• the polymerization temperature is 45°C or higher and the polymerization is carried out using a water-soluble peroxide, it is preferable to carry out the polymerization without using a reducing agent.
• a redox initiator that combines an oxidizing agent and a reducing agent as the polymerization initiator. That is, the polymerization is preferably carried out in the presence of a redox initiator.
• oxidizing agents include persulfates, organic peroxides, potassium permanganate, manganese triacetate, cerium ammonium nitrate, and bromates.
• reducing agents include sulfites, bisulfites, bromates, diimine, oxalic acid, metal sulfinic acid salts, and the like.
• Persulfates include ammonium persulfate, potassium persulfate and sodium persulfate.
• Sulfites include sodium sulfite and ammonium sulfite. It is also preferred to add a copper salt, an iron salt to the redox initiator combination in order to increase the decomposition rate of the initiator.
• Copper salts include copper (II) sulfate, and iron salts include iron (II) sulfate.
• a chelating agent ethylenediaminetetraacetic acid disodium salt dihydrate is preferred.
• redox initiators include potassium permanganate/oxalic acid, ammonium persulfate/bisulfite/iron(II) sulfate, ammonium persulfate/sulfite/iron(II) sulfate, ammonium persulfate/sulfite, ammonium persulfate/ Iron (II) sulfate, manganese triacetate/oxalic acid, cerium ammonium nitrate/oxalic acid, bromate/sulfite, bromate/bisulfite, ammonium persulfate/sodium hydroxymethanesulfinate dihydrate, etc. , ammonium persulfate/sodium hydroxymethanesulfinate dihydrate.
• either the oxidizing agent or the reducing agent may be charged in advance into the polymerization tank, and then the other may be added continuously or intermittently to initiate polymerization.
• the oxidizing agent or the reducing agent may be charged in advance into the polymerization tank, and then the other may be added continuously or intermittently to initiate polymerization.
• ammonium persulfate/sodium hydroxymethanesulfinate dihydrate it is preferable to charge ammonium persulfate into a polymerization tank and continuously add sodium hydroxymethanesulfinate dihydrate thereto.
• the amount of persulfate used in the redox initiator is preferably 0.001 to 2.0% by mass, more preferably 0.01 to 1.5% by mass, and 0.01 to 2.0% by mass, based on the aqueous medium used for polymerization. 05 to 1.0% by weight is particularly preferred.
• the amount of the reducing agent used is preferably 1 to 30% by mass, more preferably 3 to 25% by mass, and particularly preferably 5 to 20% by mass, relative to the aqueous medium used for polymerization.
• the amount of the third component (the copper salt, iron salt, etc.) used is preferably 0.001 to 0.5% by mass, more preferably 0.005 to 0.4% by mass, relative to the aqueous medium used for polymerization. is more preferable, and 0.01 to 0.3% by mass is particularly preferable.
• the fluorine-containing monomer may be polymerized in the presence of a chain transfer agent.
• chain transfer agents can be used, for example, hydrocarbons, esters, ethers, alcohols, ketones, halogen-containing compounds, carbonates and the like can be used.
• isopentane , diethyl malonate and ethyl acetate are preferable from the viewpoint that the reaction rate is less likely to decrease.
• the terminal of the polymer can be iodinated and it can be used as a reactive polymer.
• a chain transfer agent it is particularly preferable to use a bromine compound or an iodine compound.
• Polymerization methods using a bromine compound or an iodine compound include, for example, iodine transfer polymerization and bromine transfer polymerization.
• Iodine compounds and bromine compounds are water-insoluble and difficult to emulsify. Therefore, emulsion polymerization was originally limited, and there was a tendency that a large amount of surfactant had to be used. According to the production method of the present disclosure, a fluorine-containing elastomer is obtained by polymerization using an iodine compound or a bromine compound, such as iodine transfer polymerization or bromine transfer polymerization, even in the absence of conventionally used surfactants. became possible.
• Iodine transfer polymerization is radically active due to the low dissociation energy of the carbon-iodine bond, and the chain transfer reaction is involved in the process of the radical polymerization reaction. It's about how to Regarding the reaction conditions, known conditions can be used as appropriate, and are not particularly limited. The conditions described in Japanese Patent Application Laid-Open No. 53-3495 can be appropriately adopted. Similar polymerizations can be carried out using bromine compounds in place of iodine compounds, and in this disclosure such polymerizations are referred to as bromine transfer polymerizations.
• iodine transfer polymerization is preferable from the viewpoint of polymerization reactivity and cross-linking reactivity.
• bromine compounds or iodine compounds include, for example, the general formula: R 8 I x Br y (Wherein, x and y are each an integer of 0 to 2 and satisfy 1 ⁇ x + y ⁇ 2, and R 8 is a saturated or unsaturated fluorohydrocarbon group having 1 to 16 carbon atoms or chlorofluoro a hydrocarbon group, or a hydrocarbon group having 1 to 3 carbon atoms, which may contain an oxygen atom).
• a bromine compound or an iodine compound iodine or bromine is introduced into the polymer and functions as a cross-linking point.
• Bromine compounds and iodine compounds include, for example, 1,3-diiodoperfluoropropane, 2-iodoperfluoropropane, 1,3-diiodoperfluoropropane, 1,4-diiodoperfluorobutane, 1 ,5-diiodo-2,4-dichloroperfluoropentane, 1,6-diiodoperfluorohexane, 1,8-diiodoperfluorooctane, 1,12-diiodoperfluorododecane, 1,16-diiodine perfluorohexadecane, diiodomethane, 1,2-diiodoethane, 1,3-diiodo-n - propane, CF2Br2 , BrCF2CF2Br , CF3CFBrCF2Br , CFClBr2 , Br
• compounds containing only iodine and not containing bromine are preferred, such as 1,4-diiodoperfluorobutane, 1,6-diiodine Perfluorohexane or 2-iodoperfluoropropane is preferably used.
• the amount of chain transfer agent is preferably 0.2 ⁇ 10 ⁇ 3 to 2 mol %, more preferably 1.0 ⁇ 10 ⁇ 3 to 1 mol %, based on the total amount of monomers used in the polymerization. is.
• Aqueous medium means a liquid containing water.
• the aqueous medium is not particularly limited as long as it contains water.
• water and fluorine-free organic solvents such as alcohols, ethers and ketones, and/or fluorine-containing organic solvents having a boiling point of 40° C. or less. may include.
• Phosphate, sodium hydroxide, potassium hydroxide, aqueous ammonia, etc. may be used as a pH adjuster in the polymerization of the fluorine-containing monomer.
• the aqueous medium is preferably acidic.
• the pH of the aqueous medium is preferably 7 or less, more preferably 6 or less, and preferably 3 or more.
• the fluoromonomer may be polymerized in the presence or absence of the fluoromonomer polymerization seed particles.
• fluorine-containing monomer polymerized seed particles are obtained by polymerizing a fluorine-containing monomer in an aqueous medium, and include monomers and additives (e.g., polymerization Initiator, etc.) are present during the second polymerization in which the types and proportions of components such as initiators, reaction conditions, etc. are different.
• the fluoromonomer polymerized seed particles act as so-called seed particles during the polymerization of the fluoromonomer, and constitute the polymerization of the fluoromonomer in the presence of the seed particles, ie, the so-called seed polymerization. In the production method of the present disclosure, such seed polymerization may not be performed when polymerizing the fluorine-containing monomer.
• the polymerization temperature for polymerizing the fluorine-containing monomer is preferably 10 to 120°C, more preferably 20 to 100°C.
• the polymerization temperature is preferably 15 to 60°C, more preferably 18 to 55°C, and even more preferably 20 to 50°C, from the viewpoints of stability of the aqueous dispersion and reduction of adhesion rate.
• the polymerization temperature is preferably 60 to 120° C., more preferably 60 to 100° C., more preferably 70 to 100° C., because the polymerization rate is high and a fluorine-containing elastomer that gives molded articles having excellent physical properties can be obtained. 90°C is more preferred.
• the polymerization pressure for polymerizing the fluorine-containing monomer is preferably 0.5-10 MPaG, more preferably 1-7 MPaG.
• the fluorine-containing monomer is polymerized in the presence of the fluorine-containing compound (A) and the aqueous medium, so adhesion of the polymer (fluorine-containing elastomer) to the polymerization tank can be suppressed.
• the polymer adhesion rate to the polymerization tank is preferably 8% by mass or less, more preferably 4% by mass or less, still more preferably 3% by mass or less, and most preferably 2% by mass or less.
• the polymer adhesion rate is the ratio of the mass of the polymer deposit adhering to the polymerization tank after the polymerization to the total amount of the polymer (fluorine-containing elastomer) after the polymerization (adhesion rate to the polymerization tank).
• the polymer deposits include the polymer adhering to the inside of the polymerization vessel such as the inner wall of the polymerization vessel and the stirring blades after the aqueous dispersion is extracted from the polymerization vessel after the completion of polymerization, and the polymer that is released from the aqueous dispersion due to aggregation and Also included are polymers that are suspended or precipitated without being dispersed in a liquid.
• the mass of the polymer deposit is the mass after removing moisture contained in the polymer deposit by drying at 120°C.
• Polymer adhesion rate (% by mass) mass of polymer deposit/mass of obtained polymer (including deposit) x 100
• Mass of polymer obtained mass of aqueous dispersion x solid content concentration (% by mass) of aqueous dispersion/100 + mass of polymer deposit
• an aqueous dispersion of a fluorine-containing elastomer is obtained by polymerizing a fluorine-containing monomer.
• the fluorine-containing monomer is preferably a fluorine-containing monomer (excluding the fluorine-containing compound (A)), and more preferably contains no hydrophilic group.
• PMVE perfluoro(methyl vinyl ether)
• PEVE perfluoro(ethyl vinyl ether)
• PPVE perfluoro(propyl vinyl ether)
• PAVE has the formula: CF 2 ⁇ CFOCF 2 ORf c (wherein Rf c is a linear or branched perfluoroalkyl group having 1 to 6 carbon atoms, or a cyclic perfluoroalkyl group having 5 to 6 carbon atoms). An alkyl group, or a linear or branched perfluorooxyalkyl group having 2 to 6 carbon atoms containing 1 to 3 oxygen atoms) can also be used.
• Rf is a linear fluoroalkyl group
• Rf is a linear perfluoroalkyl group
• Rf preferably has 1 to 6 carbon atoms.
• fluorine-free monomers may be polymerized together with fluorine-containing monomers.
• fluorine-free monomers include ⁇ -olefin monomers having 2 to 10 carbon atoms such as ethylene, propylene, butene and pentene; methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, cyclohexyl vinyl ether, hydroxybutyl vinyl ether, butyl vinyl ether and alkyl vinyl ethers having 1 to 20 carbon atoms in the alkyl group such as , and these monomers and compounds can be used singly or in combination of two or more.
• an aqueous dispersion containing a fluorine-containing elastomer can be produced.
• the fluorine-containing elastomer obtained by the production method of the present disclosure contains methylene groups ( --CH.sub.2--) in its main chain.
• the fluorine-containing elastomer containing —CH 2 — in the main chain is not particularly limited as long as it includes a chemical structure represented by —CH 2 —. Examples include —CH 2 —CF 2 — and —CH 2 —.
• Fluorine-containing elastomers containing structures such as CH(CH 3 )—, —CH 2 —CH 2 —, —CH 2 —CF 2 —(CF 3 )—, such as vinylidene fluoride, propylene, By polymerizing ethylene, 2,3,3,3-tetrafluoropropylene, etc., it can be introduced into the main chain of the fluorine-containing elastomer.
• the content of tetrafluoroethylene units in the fluorine-containing elastomer (the content of monomer units based on tetrafluoroethylene with respect to the total monomer units of the fluorine-containing elastomer) may be less than 40 mol %.
• a partially fluorinated elastomer is preferable because it is possible to further suppress the adhesion of the fluoroelastomer to the polymerization tank while allowing the polymerization of the fluoromonomer to proceed more smoothly.
• a partially fluorinated elastomer is a fluoropolymer containing fluorine-containing monomer units and having a perfluoromonomer unit content of less than 90 mol% with respect to the total monomer units, and having a glass transition temperature of 20°C or less. and a melting peak ( ⁇ H) magnitude of 4.5 J/g or less.
• the fluorine-containing elastomer preferably contains VdF units or TFE units, and more preferably contains VDF units.
• the fluorine-containing elastomer includes VdF-based fluorine-containing elastomer, TFE/propylene (Pr)-based fluorine-containing elastomer, TFE/Pr/VdF-based fluorine-containing elastomer, ethylene (Et)/HFP-based fluorine-containing elastomer, Et/ HFP/VdF fluorine-containing elastomer, Et/HFP/TFE fluorine-containing elastomer, Et/TFE/PAVE fluorine-containing elastomer, and the like.
• VdF-based fluorine-containing elastomer TFE/Pr-based fluorine-containing elastomer, TFE/Pr/VdF-based fluorine-containing elastomer, or Et/TFE/PAVE-based fluorine-containing elastomer have good heat aging resistance and oil resistance. It is more suitable.
• a VdF-based fluorine-containing elastomer is a fluorine-containing elastomer having VdF units.
• the content of VdF units in the fluoroelastomer is preferably 20 mol% or more, more preferably 40 mol% or more, still more preferably 50 mol% or more, relative to all monomer units, Particularly preferably, it is 60 mol % or more.
• the VdF unit is preferably 20 mol% or more and 90 mol% or less, and preferably 40 mol% or more and 85 mol% of the total number of moles of the VdF unit and the monomer units based on other monomers. % or less, more preferably 45 mol % or more and 80 mol % or less, and particularly preferably 50 mol % or more and 80 mol % or less.
• VdF-based fluorine-containing elastomer are not particularly limited as long as they are copolymerizable with VdF, and for example, the above-mentioned fluorine-containing monomers can be used.
• VdF-based fluorine-containing elastomers include VdF/HFP copolymers, VdF/TFE/HFP copolymers, VdF/CTFE copolymers, VdF/CTFE/TFE copolymers, VdF/PAVE copolymers, and VdF/TFE.
• /PAVE copolymer, VdF/HFP/PAVE copolymer, VdF/HFP/TFE/PAVE copolymer, VdF/TFE/Pr copolymer, VdF/Et/HFP copolymer and VdF/fluorinated monomer At least one copolymer selected from the group consisting of the copolymers of body (2) is preferred. Moreover, it is more preferable to have at least one monomer selected from the group consisting of TFE, HFP and PAVE as a monomer other than VdF.
• VdF-based fluorine-containing elastomers include VdF/HFP copolymers, VdF/TFE/HFP copolymers, VdF/fluorine-containing monomer (2) copolymers, and VdF/PAVE copolymers.
• VdF/TFE/PAVE copolymer, VdF/HFP/PAVE copolymer and at least one copolymer selected from the group consisting of VdF/HFP/TFE/PAVE copolymer is preferred, and VdF/HFP copolymer At least one copolymer selected from the group consisting of polymers, VdF/HFP/TFE copolymers, VdF/fluoromonomer (2) copolymers and VdF/PAVE copolymers is more preferred. .
• the VdF/PAVE copolymer preferably has a VdF/PAVE composition of (65-90)/(35-10) (mol %).
• the composition of VdF/PAVE is also one of the preferred forms in which it is (50 to 78)/(50 to 22) (mol %).
• the VdF/TFE/PAVE copolymer preferably has a VdF/TFE/PAVE composition of (40-80)/(3-40)/(15-35) (mol %).
• the VdF/HFP/PAVE copolymer preferably has a VdF/HFP/PAVE composition of (65-90)/(3-25)/(3-25) (mol %).
• the composition of VdF/HFP/TFE/PAVE is (40-90)/(0-25)/(0-40)/(3-35) (mol%) is preferred, and (40 to 80)/(3 to 25)/(3 to 40)/(3 to 25) (mol%) is more preferred.
• the copolymer of VdF/fluorine-containing monomer (2) has a VdF/fluorine-containing monomer (2) unit of (85 to 20)/(15 to 80) (mol %), and contains VdF and Monomer units other than the fluorine-containing monomer (2) are preferably 0 to 50 mol% of the total monomer units, and the mol% ratio of VdF/fluorine-containing monomer (2) units is (80 ⁇ 20)/(20-80) is more preferred.
• the composition of VdF/fluorine-containing monomer (2) units is (78-50)/(22-50) (mol %).
• the VdF/fluorine-containing monomer (2) unit is (85 to 50)/(15 to 50) (mol%), and VdF And it is also preferable that monomer units other than the fluorine-containing monomer (2) are 1 to 50 mol % of the total monomer units.
• VdF and the fluorine-containing monomer (2) include TFE, HFP, PMVE, perfluoroethyl vinyl ether (PEVE), PPVE, CTFE, trifluoroethylene, hexafluoroisobutene, vinyl fluoride,
• PEVE perfluoroethyl vinyl ether
• CTFE trifluoroethylene
• hexafluoroisobutene vinyl fluoride
• the monomers exemplified as other monomers in the VdF fluorine-containing elastomer such as Et, Pr, alkyl vinyl ethers, and monomers that provide crosslinkable groups, are preferred, among which PMVE, CTFE, HFP, and TFE are preferred. more preferred.
• a TFE/Pr-based fluorine-containing elastomer refers to a fluorine-containing copolymer composed of 45 to 70 mol% of TFE and 55 to 30 mol% of Pr.
• a specific third component may be included.
• Specific third components include, for example, fluorine-containing olefins other than TFE (e.g., VdF, HFP, CTFE, perfluoro(butyl ethylene), etc.), fluorine-containing vinyl ethers (perfluoro(propyl vinyl ether), perfluoro(methyl vinyl ether) etc.); ⁇ -olefins (ethylene, 1-butene, etc.), vinyl ethers (ethyl vinyl ether, butyl vinyl ether, hydroxybutyl vinyl ether, etc.), vinyl esters (vinyl acetate, vinyl benzoate, crotonic acid (vinyl, vinyl methacrylate, etc.);
• the specific third component may be used alone or in combination of two or more.
• the TFE/Pr-based fluorine-containing elastomer preferably contains VdF, and among the TFE/Pr-based fluorine-containing elastomers, an elastomer composed of TFE, Pr, and VdF is called a TFE/Pr/VdF-based fluorine-containing elastomer.
• the TFE/Pr/VdF fluorine-containing elastomer may further contain the above specific third component other than VdF.
• the specific third component may be used alone or in combination of two or more.
• the total content of the third component in the TFE/Pr fluorine-containing elastomer is preferably 35 mol% or less, more preferably 33 mol% or less, and even more preferably 31 mol% or less.
• the Et/HFP copolymer preferably has an Et/HFP composition of (35 to 80)/(65 to 20) (mol %), (40 to 75)/(60 to 25) (mol %) is more preferred.
• the Et/HFP/TFE copolymer preferably has an Et/HFP/TFE composition of (35 to 75)/(25 to 50)/(0 to 15) (mol%), and (45 to 75 )/(25-45)/(0-10) (mol %) is more preferable.
• the Et/TFE/PAVE copolymer preferably has an Et/TFE/PAVE composition of (10 to 40)/(32 to 60)/(20 to 40) (mol%), and (20 to 40 )/(40 to 50)/(20 to 30) (mol %) is more preferable.
• PMVE is preferred as PAVE.
• the fluorine-containing elastomer is preferably a fluorine-containing elastomer containing VdF units, more preferably a VdF/HFP copolymer or a VdF/HFP/TFE copolymer, and the composition of VdF/HFP/TFE is (32 to 85)/( 10-34)/(0-40) (mol %) is particularly preferred.
• the composition of VdF / HFP / TFE is more preferably (32-85) / (15-34) / (0-34) (mol%), (47-81) / (17-32) / (0- 26) (mol%) is more preferred.
• the composition of VdF/HFP is preferably (45 to 85) / (15 to 55) (mol%), more preferably (50 to 83) / (17 ⁇ 50) (mol%), more preferably (55 to 81) / (19 to 45) (mol%), particularly preferably (60 to 80) / (20 to 40) (mol%) be.
• the configuration described above is the configuration of the main monomer of the fluorine-containing elastomer, and in addition to the main monomer, a monomer that provides a crosslinkable group may be copolymerized.
• a monomer that provides the crosslinkable group any monomer can be used as long as it can introduce an appropriate crosslinkable group into the fluorine-containing elastomer depending on the production method and the crosslinking system.
• Known polymerizable compounds containing crosslinkable groups such as bonds, cyano groups, carboxyl groups, hydroxyl groups, amino groups, and ester groups can be mentioned.
• CY 1 2 CY 2 R f 2 X 1 (3)
• Y 1 and Y 2 are fluorine atoms, hydrogen atoms or —CH 3
• R f 2 may have one or more etheric oxygen atoms, may have an aromatic ring, linear or branched fluorine-containing alkylene group in which some or all of the hydrogen atoms are substituted with fluorine atoms
• X 1 is an iodine atom or a bromine atom
• linear or branched chain fluorine-containing alkylene group that is, a linear or branched chain fluorine-containing alkylene group in which some or all of the hydrogen atoms are substituted with fluorine atoms, some or all of the hydrogen atoms
• R 1 is a hydrogen atom or a methyl group
• CY 4 2 CY 4 (CF 2 ) n - X 1 (5)
• Y 4 are the same or different, a hydrogen atom or a fluorine atom, n is an integer of 1 to 8)
• CF2 CFCF2Rf4 -
• iodine- or bromine-containing monomer represented by general formula (4) general formula (23): (Wherein, m is an integer of 1 to 5, n is an integer of 0 to 3)
• An iodine-containing fluorinated vinyl ether represented by Among these, ICH 2 CF 2 CF 2 OCF CF 2 is preferred.
• "(per)fluoropolyoxyalkylene group” means "fluoropolyoxyalkylene group or perfluoropolyoxyalkylene group”.
• Z is preferably a (per)fluoroalkylene group having 4 to 12 carbon atoms, and R 2 , R 3 , R 4 , R 5 , R 6 and R 7 are preferably hydrogen atoms.
• Z is a (per)fluoropolyoxyalkylene group, the formula: -(Q) p -CF 2 O-(CF 2 CF 2 O) m -(CF 2 O) n -CF 2 -(Q) p - (In the formula, Q is an alkylene group having 1 to 10 carbon atoms or an oxyalkylene group having 2 to 10 carbon atoms, p is 0 or 1, and m and n have an m/n ratio of 0.2 to 5. and the molecular weight of the (per)fluoropolyoxyalkylene group is an integer in the range of 500 to 10,000, preferably 1,000 to 4,000.) is preferably a (per)fluoropolyoxyalkylene group represented by .
• the number average molecular weight Mn of the fluorine-containing elastomer is preferably 1,000 to 1,000,000, more preferably 10,000 to 500,000, and particularly preferably 20,000 to 300,000.
• the fluorine content of the fluorine-containing elastomer is preferably 50% by mass or more, more preferably 55% by mass or more, and even more preferably 60% by mass or more.
• the upper limit of the fluorine content is preferably 75% by mass or less, more preferably 73% by mass or less.
• the fluorine content is calculated based on the values measured by 19 F-NMR, 1 H-NMR, elemental analysis, and the like.
• the fluorine-containing elastomer preferably has a Mooney viscosity at 100°C (ML1+10 (100°C)) of 130 or less.
• the Mooney viscosity is more preferably 110 or less, even more preferably 90 or less.
• the Mooney viscosity is more preferably 10 or more, and still more preferably 20 or more.
• the Mooney viscosity is a value measured according to JIS K 6300-1.2013.
• the fluorine-containing elastomer preferably has a glass transition temperature of -50 to 0°C.
• the glass transition temperature is more preferably ⁇ 2° C. or lower, still more preferably ⁇ 3° C. or lower. Further, the glass transition temperature is more preferably ⁇ 45° C. or higher, further preferably ⁇ 40° C. or higher.
• the glass transition temperature may be -10°C or higher, or -9°C or higher.
• the glass transition temperature is measured using a differential scanning calorimeter (e.g., X-DSC7000 manufactured by Hitachi High-Tech Science) to obtain a DSC curve by heating 10 mg of the sample at 20 ° C./min, according to JIS K6240: 2011. , the glass transition temperature can be obtained from the DSC differential curve.
• a differential scanning calorimeter e.g., X-DSC7000 manufactured by Hitachi High-Tech Science
• the fluorine-containing elastomer preferably has an iodine content of 0.05 to 1.0% by mass.
• the iodine content is more preferably 0.08% by mass or more, still more preferably 0.10% by mass or more, and more preferably 0.80% by mass or less, and even more preferably 0.60% by mass or less.
• the iodine content can be determined by elemental analysis. Specifically, 5 mg of Na 2 SO 3 was mixed with 12 mg of fluorine-containing elastomer, and 30 mg of Na 2 CO 3 and K 2 CO 3 were mixed in 20 ml of pure water at a ratio of 1:1 (mass ratio). can be used, burned in oxygen in a quartz flask, allowed to stand for 30 minutes, and then measured using a Shimadzu 20A ion chromatograph. As a calibration curve, a KI standard solution, one containing 0.5 ppm by mass of iodine ions, and one containing 1.0 ppm by mass of iodine ions can be used.
• the fluorine-containing elastomer preferably contains a —CH 2 I structure.
• the inclusion of the —CH 2 I structure can be confirmed by the 1 H-NMR spectrum.
• a fluorine-containing elastomer containing a —CH 2 I structure can be obtained by iodine transfer polymerization.
• the fluorine-containing elastomer preferably contains 0.05 to 1.50 mol % of the --CH 2 I structure relative to 100 mol % of the --CH 2 -- structure.
• the amount of the —CH 2 I structure is more preferably 0.08 mol% or more, still more preferably 0.12 mol% or more, more preferably 1.20 mol% or less, further preferably 1.00 mol% or less, and 0 0.80 mol % or less is particularly preferred.
• the amount of —CH 2 I structure can be determined from the 1 H-NMR spectrum.
• the fluorine-containing elastomer more preferably contains a —CF 2 CH 2 I structure.
• a fluorine-containing elastomer containing a —CF 2 CH 2 I structure can be obtained by producing a VdF-based fluorine-containing elastomer by iodine transfer polymerization.
• the fluorine-containing elastomer preferably contains 0.05 to 1.50 mol % of the -CF 2 CH 2 I structure with respect to 100 mol % of the -CH 2 - structure.
• the amount of the —CF 2 CH 2 I structure is more preferably 0.08 mol % or more, still more preferably 0.12 mol % or more, more preferably 1.20 mol % or less, and even more preferably 1.00 mol % or less. , 0.80 mol % or less is particularly preferred.
• the amount of the —CF 2 CH 2 I structure is the integrated value A of all peak intensities observed in the chemical shift region of 3.75 to 4.05 ppm derived from —CH 2 I in the 1 H-NMR spectrum, and —CH It is calculated by A/B*100 from the integrated value B of all peak intensities observed in the chemical shifts 2.3 to 2.7 ppm and 2.9 to 3.75 ppm derived from 2- .
• the fluoromonomers described for the fluoroelastomer can be appropriately used.
• the production method of the present disclosure can efficiently produce a fluorine-containing elastomer by using at least one fluorine-containing compound (A).
• two or more fluorine-containing compounds (A) may be used at the same time, and those having volatility or those that may remain in the molded article containing the fluorine-containing elastomer may be used.
• other compounds having surfactant activity may be used at the same time.
• a fluorine-containing single It is preferably one that polymerizes a monomer.
• a fluorine-containing surfactant has been used in the polymerization of fluorine-containing monomers, but the production method of the present disclosure eliminates the use of a fluorine-containing surfactant by using the fluorine-containing compound (A).
• a fluorine-containing elastomer can be obtained by polymerizing a fluorine-containing monomer.
• substantially in the absence of a fluorine-containing surfactant means that the content of the fluorine-containing surfactant in the aqueous medium is 10 ppm by mass or less, and the fluorine-containing surfactant
• the content of the agent is preferably 1 mass ppm or less, more preferably 100 mass ppb or less, still more preferably 10 mass ppb or less, and particularly preferably 1 mass ppb or less.
• fluorine-containing surfactant examples include anionic fluorine-containing surfactants.
• the anionic fluorine-containing surfactant may be, for example, a surfactant containing fluorine atoms having a total carbon number of 20 or less in the portion excluding anionic groups.
• the fluorine-containing surfactant may also be a fluorine-containing surfactant whose anionic moiety has a molecular weight of 1000 or less, preferably 800 or less.
• the "anionic portion” means the portion of the fluorine-containing surfactant excluding the cation.
• F(CF 2 ) n1 COOM represented by formula (I) described later, it is the “F(CF 2 ) n1 COO” portion.
• the fluorine-containing surfactant also includes a fluorine-containing surfactant having a LogPOW of 3.5 or less.
• the above LogPOW is the partition coefficient between 1-octanol and water, and LogP [wherein P is the octanol/water (1:1) mixture containing the fluorine-containing surfactant during phase separation. represents the concentration ratio of the fluorine-containing surfactant/the concentration of the fluorine-containing surfactant in water].
• fluorine-containing surfactant examples include US Patent Application Publication No. 2007/0015864, US Patent Application Publication No. 2007/0015865, US Patent Application Publication No. 2007/0015866, and US Patent Published Application No. 2007/0276103, U.S. Published Application No. 2007/0117914, U.S. Published Application No. 2007/0142541, U.S. Published Application No. 2008/0015319, U.S. Patent No. 3250808 Specification, US Patent No. 3271341, JP 2003-119204, WO 2005/042593, WO 2008/060461, WO 2007/046377, JP 2007-119526 Publications, International Publication No. 2007/046482, International Publication No. 2007/046345, U.S. Patent Application Publication No. 2014/0228531, International Publication No. 2013/189824, International Publication No. 2013/189826, etc. mentioned.
• anionic fluorine-containing surfactant As the anionic fluorine-containing surfactant, the following general formula (N 0 ): X n0 ⁇ Rf n0 ⁇ Y 0 (N 0 ) (Wherein, X n0 is H, Cl or and F. Rf n0 has 3 to 20 carbon atoms and is linear, branched or cyclic, and some or all of H is replaced by F is an alkylene group, the alkylene group may contain one or more ether bonds, and some H may be substituted with Cl. Y 0 is an anionic group.) The compound represented by mentioned.
• the anionic group of Y 0 may be -COOM, -SO 2 M, or -SO 3 M, and may be -COOM or -SO 3 M.
• M is H, a metal atom, NR 74 , optionally substituted imidazolium , optionally substituted pyridinium or optionally substituted phosphonium ; is -H or an organic group.
• metal atoms examples include alkali metals (group 1) and alkaline earth metals (group 2), such as Na, K or Li.
• R 7 may be —H or a C 1-10 organic group, —H or a C 1-4 organic group, or —H or a C 1-4 alkyl group.
• M may be H, a metal atom or NR 7 4 , may be H, an alkali metal (group 1), an alkaline earth metal (group 2) or NR 7 4 , H, Na, K, Li or NH4 .
• Rf n0 50% or more of H may be substituted with fluorine.
• N 0 As the compound represented by the general formula (N 0 ), The following general formula (N 1 ): X n0 ⁇ (CF 2 ) m1 ⁇ Y 0 (N 1 ) (Wherein, X n0 are H, Cl and F, m1 is an integer of 3 to 15, and Y 0 is as defined above.)
• Rf n5 is a linear or branched partially or fully fluorinated alkylene group that may contain an ether bond of 1 to 3 carbon atoms, and L is a linking group; , Y 0 are as defined above, provided that the total number of carbon atoms of X n2 , X n3 , X n4 and Rf n5 is 18 or less.
• the compounds represented by the general formula (N 0 ) include perfluorocarboxylic acids (I) represented by the following general formula (I), ⁇ -H represented by the following general formula (II) Perfluorocarboxylic acid (II), perfluoroethercarboxylic acid (III) represented by the following general formula (III), perfluoroalkylalkylenecarboxylic acid (IV) represented by the following general formula (IV), the following general formula Perfluoroalkoxyfluorocarboxylic acid (V) represented by (V), perfluoroalkylsulfonic acid (VI) represented by the following general formula (VI), ⁇ -H perm represented by the following general formula (VII) fluorosulfonic acid (VII), perfluoroalkylalkylenesulfonic acid (VIII) represented by the following general formula (VIII), alkylalkylenecarboxylic acid (IX) represented by the following general formula (IX), the following general formula (X ), the
• the perfluorocarboxylic acid (I) has the following general formula (I) F( CF2 ) n1COOM (I) (In the formula, n1 is an integer of 3 to 14 , M is H, a metal atom, NR 74 , imidazolium optionally having substituents, pyridinium optionally having substituents or It is a phosphonium which may have a substituent, and R 7 is —H or an organic group.).
• the ⁇ -H perfluorocarboxylic acid (II) has the following general formula (II) H(CF2) n2COOM ( II ) (wherein n2 is an integer of 4 to 15, and M is as defined above).
• the perfluoroether carboxylic acid (III) has the following general formula (III) Rf 1 -O-(CF(CF 3 )CF 2 O) n3 CF(CF 3 )COOM (III) (Wherein, Rf 1 is a perfluoroalkyl group having 1 to 5 carbon atoms, n3 is an integer of 0 to 3, and M is as defined above.) .
• the perfluoroalkylalkylenecarboxylic acid (IV) has the following general formula (IV) Rf2(CH2)n4Rf3COOM ( IV ) (In the formula, Rf 2 is a perfluoroalkyl group having 1 to 5 carbon atoms, Rf 3 is a linear or branched perfluoroalkylene group having 1 to 3 carbon atoms, n4 is 1 to 3 and M is defined above).
• the alkoxyfluorocarboxylic acid (V) has the following general formula (V) Rf4 - O - CY1Y2CF2 - COOM (V) (Wherein, Rf 4 is a linear or branched partially or fully fluorinated alkyl group which may contain an ether bond and/or a chlorine atom having 1 to 12 carbon atoms, and Y 1 and Y 2 are , which are the same or different, are H or F, and M is as defined above.
• the perfluoroalkylsulfonic acid (VI) has the following general formula (VI) F( CF2)n5SO3M ( VI ) (wherein n5 is an integer of 3 to 14, and M is as defined above).
• the ⁇ -H perfluorosulfonic acid (VII) has the following general formula (VII) H( CF2)n6SO3M ( VII ) (wherein n6 is an integer of 4 to 14, and M is as defined above).
• the perfluoroalkylalkylene sulfonic acid (VIII) has the following general formula (VIII) Rf5 ( CH2 ) n7SO3M ( VIII) (Wherein, Rf 5 is a perfluoroalkyl group having 1 to 13 carbon atoms, n7 is an integer of 1 to 3, and M is as defined above.) .
• the alkylalkylenecarboxylic acid (IX) has the following general formula (IX) Rf6 ( CH2 ) n8COOM (IX) (wherein Rf 6 is a linear or branched partially or fully fluorinated alkyl group which may contain an ether bond with 1 to 13 carbon atoms, n8 is an integer of 1 to 3, M is defined above.).
• the fluorocarboxylic acid (X) has the following general formula (X) Rf7 - O - Rf8 - O-CF2-COOM(X) (Wherein, Rf 7 is a linear or branched partially or fully fluorinated alkyl group which may contain ether bonds and/or chlorine atoms having 1 to 6 carbon atoms, and Rf 8 is a carbon number 1 to 6 linear or branched, partially or fully fluorinated alkyl groups, and M is as defined above.
• the alkoxyfluorosulfonic acid (XI) has the following general formula (XI) Rf9 -O - CY1Y2CF2 - SO3M (XI) (wherein Rf 9 is a linear or branched chained alkyl group which may contain an ether bond of 1 to 12 carbon atoms and which may contain chlorine and may be partially or fully fluorinated; Y 1 and Y 2 are the same or different and are H or F, and M is as defined above).
• the above compound (XII) has the following general formula (XII): (Wherein, X 1 , X 2 and X 3 may be the same or different, and may contain H, F and an ether bond having 1 to 6 carbon atoms, a linear or branched partially or fully fluorinated Rf 10 is a perfluoroalkylene group having 1 to 3 carbon atoms, L is a linking group, and Y 0 is an anionic group.).
• Y 0 may be -COOM, -SO 2 M, or -SO 3 M, and may be -SO 3 M, or -COOM, where M is as defined above.
• L includes, for example, a single bond, a partially fluorinated alkylene group that may contain an ether bond having 1 to 10 carbon atoms, or a fully fluorinated alkylene group.
• the above compound (XIII) has the following general formula (XIII): Rf 11 —O—(CF 2 CF(CF 3 )O) n9 (CF 2 O) n10 CF 2 COOM (XIII) (wherein Rf 11 is a chlorine-containing fluoroalkyl group having 1 to 5 carbon atoms, n9 is an integer of 0 to 3, n10 is an integer of 0 to 3, and M is the above-defined It is represented by Compound (XIII) includes CF2ClO ( CF2CF ( CF3 )O) n9 ( CF2O ) n10CF2COONH4 ( a mixture with an average molecular weight of 750, where n9 and n10 are as defined above). There is.)
• the fluorine-containing surfactant may be one type of fluorine-containing surfactant, or may be a mixture containing two or more types of fluorine-containing surfactants.
• fluorine-containing surfactants include compounds represented by the following formulas.
• a fluorine-containing surfactant may be a mixture of these compounds.
• the fluoromonomer is polymerized substantially in the absence of a compound of the formula: F( CF2 ) 7COOM , F ( CF2) 5COOM , H( CF2 ) 6COOM , H( CF2 ) 7COOM , CF3O ( CF2) 3OCHFCF2COOM , C3F7OCF ( CF3 ) CF2OCF ( CF3 )COOM, CF3CF2CF2OCF ( CF3 )COOM , CF3CF2OCF2CF2OCF2COOM , _ _ _ C2F5OCF ( CF3 ) CF2OCF ( CF3 )COOM, CF3OCF ( CF3 ) CF2OCF ( CF3 )COOM, CF2F ( CF3 )
• an aqueous dispersion of a fluorine-containing elastomer is obtained.
• the solid content concentration (content of the fluoroelastomer) of the fluoroelastomer aqueous dispersion to be obtained is preferably 10 to 50% by mass, more preferably 15 to 40% by mass, at the time of completion of polymerization, More preferably, it is 20 to 30% by mass.
• the solid content concentration (content of the fluorine-containing elastomer) of the fluorine-containing elastomer aqueous dispersion is determined by drying 1 g of the aqueous dispersion under the conditions of 150° C. for 180 minutes and measuring the mass of the heating residue. It can be specified by calculating the ratio of the mass of the heating residue to the mass.
• the aqueous dispersion of the fluoroelastomer may contain fluoroelastomer particles.
• the average particle size of the fluorine-containing elastomer particles is preferably 10 to 800 nm, more preferably 50 to 500 nm, still more preferably 70 to 300 nm.
• the average particle size of the fluorine-containing elastomer particles is the cumulant average size, which can be measured by a dynamic light scattering method.
• the number of fluorine-containing elastomer particles contained in the aqueous dispersion of the fluorine-containing elastomer is preferably 1.0 ⁇ 10 12 particles/cc or more, more preferably 5.0 ⁇ 10 12 particles/cc or more. More preferably, it is 1.0 ⁇ 10 13 particles/cc or more, particularly preferably 1.2 ⁇ 10 14 particles/cc or more, and most preferably 1.3 ⁇ 10 14 particles/cc or more.
• the number of particles (the number of polymer particles) can be calculated according to the following formula.
• the number of fluorine-containing elastomer particles obtained by the above formula is the number per 1 cc of water.
• the specific gravity is the specific gravity of the fluorine-containing elastomer.
• the specific gravity of the fluorine-containing elastomer can be obtained according to JIS Z 8807:2012.
• the aqueous dispersion of the fluorine-containing elastomer may be subjected to treatments such as coagulation and heating.
• the above coagulation can be carried out by adding alkaline earth and earth metal salts to the aqueous dispersion.
• Alkaline earth and earth metal salts include sulfates, nitrates, hydrochlorides, acetates, etc. of calcium, magnesium, aluminum, and the like.
• the coagulated fluorine-containing elastomer may be washed with water to remove impurities such as a small amount of buffer solution and salt present in the fluorine-containing elastomer, and then the washed fluorine-containing elastomer may be dried.
• the drying temperature is preferably 40 to 200°C, more preferably 60 to 180°C, still more preferably 80 to 150°C.
• the form of the fluorine-containing elastomer obtained after coagulation is not particularly limited, but may be gum, crumb, powder, pellet, etc., preferably gum or crumb. Gum is a small granular lump made of a fluorine-containing elastomer, and crumb is a fluorine-containing elastomer that cannot maintain its shape as a gum at room temperature and fuses with each other. It is in the shape of an amorphous mass.
• the gum or crumb is preferably obtained from the aqueous dispersion obtained by the production method of the present disclosure by coagulation, drying, etc. by conventionally known methods.
• a fluorine-containing elastomer composition can be produced by adding a cross-linking agent or the like to the fluorine-containing elastomer aqueous dispersion or the fluorine-containing elastomer obtained by the production method of the present disclosure.
• the type and amount of the cross-linking agent are not particularly limited, and can be used within a known range.
• the crosslinked system includes, for example, a peroxide crosslinked system, a polyol crosslinked system, a polyamine crosslinked system, etc., and is selected from the group consisting of a peroxide crosslinked system and a polyol crosslinked system. At least one selected is preferred. From the viewpoint of chemical resistance, a peroxide crosslinked system is preferred, and from the viewpoint of heat resistance, a polyol crosslinked system is preferred.
• the cross-linking agent is preferably at least one cross-linking agent selected from the group consisting of a polyol cross-linking agent and a peroxide cross-linking agent, more preferably a peroxide cross-linking agent.
• the amount of the cross-linking agent to be blended may be appropriately selected according to the type of the cross-linking agent, etc., but it is preferably 0.2 to 6.0 parts by mass, more preferably 0.3 parts by mass, per 100 parts by mass of the fluorine-containing elastomer. ⁇ 5.0 parts by mass.
• Peroxide crosslinking can be performed by using an uncrosslinked elastomer capable of peroxide crosslinking as the fluorine-containing elastomer and an organic peroxide as the crosslinking agent.
• the uncrosslinked elastomer that can be peroxide-crosslinked is not particularly limited as long as it has a site that can be peroxide-crosslinked.
• the peroxide-crosslinkable site is not particularly limited, and examples thereof include a site having an iodine atom, a site having a bromine atom, and the like.
• the organic peroxide may be any organic peroxide that can easily generate peroxy radicals in the presence of heat or a redox system, such as 1,1-bis(t-butylperoxy)-3, 5,5-trimethylcyclohexane, 2,5-dimethylhexane-2,5-dihydroperoxide, di-t-butyl peroxide, t-butylcumyl peroxide, dicumyl peroxide, ⁇ , ⁇ -bis(t- Butylperoxy)-p-diisopropylbenzene, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-dimethyl-2,5-di(t-butylperoxy)-hexyne -3, benzoyl peroxide, t-butylperoxybenzene, t-butylperoxymaleic acid, t-butylperoxyisopropyl carbonate, t-buty
• the blending amount of the organic peroxide is preferably 0.1 to 15 parts by mass, more preferably 0.3 to 5 parts by mass, per 100 parts by mass of the fluorine-containing elastomer.
• the fluorine-containing elastomer composition preferably further contains a cross-linking aid.
• crosslinking aids include triallyl cyanurate, triallyl isocyanurate (TAIC), triacrylformal, triallyl trimellitate, N,N'-m-phenylenebismaleimide, dipropagyl terephthalate, diallyl phthalate, Tetraallyl terephthalate amide, triallyl phosphate, bismaleimide, fluorinated triallyl isocyanurate (1,3,5-tris(2,3,3-trifluoro-2-propenyl)-1,3,5-triazine-2 ,4,6-trione), tris(diallylamine)-S-triazine, N,N-diallylacrylamide, 1,6-divinyldodecafluorohexane, hexaallylphosphoramide, N,N,N',N'-te
• the amount of the cross-linking aid compounded is preferably 0.01 to 10 parts by mass, more preferably 0.01 to 7.0 parts by mass, and still more preferably 0 parts by mass with respect to 100 parts by mass of the fluorine-containing elastomer. .1 to 5.0 parts by mass. If the cross-linking coagent is less than 0.01 part by mass, the mechanical properties and the flexibility may deteriorate. If the amount exceeds 10 parts by mass, the heat resistance tends to be poor and the durability of the molded product tends to decrease.
• Polyol crosslinking can be performed by using an uncrosslinked elastomer that can be polyol-crosslinked as a fluorine-containing elastomer and a polyhydroxy compound as a crosslinking agent.
• the blending amount of the polyhydroxy compound in the polyol cross-linkable system is preferably 0.01 to 10 parts by mass with respect to 100 parts by mass of the uncrosslinked elastomer capable of being polyol-crosslinked.
• the polyol crosslinking can be sufficiently advanced. More preferably, it is 0.02 to 8 parts by mass. More preferably, it is 0.03 to 4 parts by mass.
• the polyol-crosslinkable uncrosslinked elastomer is not particularly limited as long as it has a polyol-crosslinkable site.
• the polyol-crosslinkable site is not particularly limited, and examples thereof include sites having vinylidene fluoride (VdF) units.
• Examples of the method for introducing the cross-linking site include a method of copolymerizing a monomer that provides the cross-linking site during polymerization of the uncrosslinked elastomer.
• polyhydroxy compound a polyhydroxy aromatic compound is preferably used because of its excellent heat resistance.
• the polyhydroxyaromatic compound is not particularly limited, and examples thereof include 2,2-bis(4-hydroxyphenyl)propane (hereinafter referred to as bisphenol A), 2,2-bis(4-hydroxyphenyl)perfluoropropane. (hereinafter referred to as bisphenol AF.
• Bisphenol AF is available from, for example, Fuji Film Wako Pure Chemical Industries, Ltd., Central Glass Co., Ltd., etc.), 1,3-dihydroxybenzene, 1,7-dihydroxynaphthalene, 2,7-dihydroxynaphthalene , 1,6-dihydroxynaphthalene, 4,4′-dihydroxydiphenyl, 4,4′-dihydroxystilbene, 2,6-dihydroxyanthracene, hydroquinone, catechol, 2,2-bis(4-hydroxyphenyl)butane (hereinafter referred to as bisphenol B), 4,4-bis(4-hydroxyphenyl)valeric acid, 2,2-bis(4-hydroxyphenyl)tetrafluorodichloropropane, 4,4'-dihydroxydiphenylsulfone, 4,4'-dihydroxy diphenyl ketone, tri(4-hydroxyphenyl)methane, 3,3′,5,5′-tetrachlorobisphenol A, 3,3
• polyhydroxyaromatic compounds may be alkali metal salts, alkaline earth metal salts, etc. However, when the copolymer is coagulated using an acid, it is preferable not to use the above metal salts.
• the blending amount of the polyhydroxyaromatic compound is 0.1 to 15 parts by mass, preferably 0.5 to 5 parts by mass, per 100 parts by mass of the uncrosslinked elastomer.
• the fluorine-containing elastomer composition preferably further contains a cross-linking accelerator.
• the cross-linking accelerator promotes the formation of intramolecular double bonds in the dehydrofluoric acid reaction of the polymer main chain and the addition of the polyhydroxy compound to the generated double bonds.
• the cross-linking accelerator may be used in combination with an acid acceptor such as magnesium oxide, or a cross-linking aid.
• crosslinking accelerator examples include onium compounds.
• onium compounds ammonium compounds such as quaternary ammonium salts, phosphonium compounds such as quaternary phosphonium salts, oxonium compounds, sulfonium compounds, cyclic amines, and 1 It is preferably at least one selected from the group consisting of functional amine compounds, more preferably at least one selected from the group consisting of quaternary ammonium salts and quaternary phosphonium salts.
• the quaternary ammonium salt is not particularly limited, and examples include 8-methyl-1,8-diazabicyclo[5,4,0]-7-undecenium chloride, 8-methyl-1,8-diazabicyclo[5, 4,0]-7-undecenium iodide, 8-methyl-1,8-diazabicyclo[5,4,0]-7-undecenium hydroxide, 8-methyl-1,8-diazabicyclo[5 ,4,0]-7-undecenium methyl sulfate, 8-ethyl-1,8-diazabicyclo[5,4,0]-7-undecenium bromide, 8-propyl-1,8-diazabicyclo[5 ,4,0]-7-undecenium bromide, 8-dodecyl-1,8-diazabicyclo[5,4,0]-7-undecenium chloride, 8-dodecyl-1,8-diazabicyclo[5,4 ,
• DBU-B is, for example, available from Fuji Film Wako Pure Chemical Industries, Ltd.), 8-benzyl-1,8-diazabicyclo[5,4,0]-7-undecenium hydroxide, 8-phenethyl-1,8-diazabicyclo[5 ,4,0]-7-undecenium chloride, 8-(3-phenylpropyl)-1,8-diazabicyclo[5,4,0]-7-undecenium chloride, tetrabutylammonium hydrogen sulfate, tetra butylammonium hydroxide, tetrabutylammonium chloride, tetrabutylammonium bromide and the like.
• DBU-B is preferable from the viewpoint of crosslinkability, mechanical properties and flexibility.
• the quaternary phosphonium salt is not particularly limited, and examples thereof include tetrabutylphosphonium chloride, benzyltriphenylphosphonium chloride (hereinafter referred to as BTPPC), benzyltrimethylphosphonium chloride, benzyltributylphosphonium chloride, tributylallylphosphonium chloride, tributyl -2-methoxypropyl phosphonium chloride, benzylphenyl (dimethylamino) phosphonium chloride, and the like.
• BTPPC benzyltriphenylphosphonium chloride
• BTPPC benzyltriphenylphosphonium chloride
• cross-linking accelerator a solid solution of a quaternary ammonium salt and bisphenol AF, a solid solution of a quaternary phosphonium salt and bisphenol AF, and a chlorine-free cross-linking accelerator disclosed in JP-A-11-147891 are used.
• a cross-linking accelerator a solid solution of a quaternary ammonium salt and bisphenol AF, a solid solution of a quaternary phosphonium salt and bisphenol AF, and a chlorine-free cross-linking accelerator disclosed in JP-A-11-147891 are used.
• the amount of the crosslinking accelerator to be blended is preferably 0.01 to 8.00 parts by mass, more preferably 0.02 to 5.00 parts by mass, per 100 parts by mass of the uncrosslinked elastomer. More preferably, it is 0.03 to 3.00 parts by mass. If the amount of the cross-linking accelerator is less than 0.01 parts by mass, the cross-linking of the uncross-linked elastomer may not proceed sufficiently, and the resulting molded article may have reduced heat resistance. If it exceeds 8.00 parts by mass, there is a possibility that the molding processability of the fluorine-containing elastomer composition will be deteriorated, the elongation in mechanical properties will be deteriorated, and the flexibility will also tend to be deteriorated.
• Acid acceptors are used to neutralize acidic substances generated during polyol cross-linking. #2000, CALDIC #1000 (manufactured by Ohmi Chemical Industry Co., Ltd.)), calcium oxide, litharge (lead oxide), zinc white, dibasic lead phosphite, hydrotalcite, etc., and highly active magnesium oxide and low It is preferably at least one selected from the group consisting of active magnesium.
• Polyamine crosslinking can be performed by using a polyamine-crosslinkable fluorine-containing elastomer as a fluorine-containing elastomer and a polyamine compound as a crosslinking agent.
• the polyamine-crosslinkable fluorine-containing elastomer is not particularly limited as long as it has a polyamine-crosslinkable site.
• the polyamine-crosslinkable site is not particularly limited, and examples thereof include sites having vinylidene fluoride (VdF) units.
• Examples of the method for introducing the cross-linking site include a method of copolymerizing a monomer that provides the cross-linking site during polymerization of the fluorine-containing elastomer.
• polyamine compounds examples include hexamethylenediamine carbamate, N,N'-dicinnamylidene-1,6-hexamethylenediamine, and 4,4'-bis(aminocyclohexyl)methane carbamate. Among these, N,N'-dicinnamylidene-1,6-hexamethylenediamine is preferred.
• the method for obtaining the fluoroelastomer composition is not particularly limited as long as the fluoroelastomer obtained by the production method of the present disclosure and the cross-linking agent can be uniformly mixed.
• the fluorine-containing elastomer composition may contain at least one polyfunctional compound.
• a polyfunctional compound is a compound having two or more functional groups with the same or different structures in one molecule.
• Functional groups possessed by polyfunctional compounds include functional groups generally known to have reactivity, such as carbonyl groups, carboxyl groups, haloformyl groups, amide groups, olefin groups, amino groups, isocyanate groups, hydroxy groups, and epoxy groups. Any group can be used.
• the fluorine-containing elastomer composition may optionally contain conventional additives blended into the elastomer, such as fillers (carbon black, barium sulfate, etc.), processing aids (wax, etc.), plasticizers, colorants, and stabilizers. , tackifiers (coumarone resin, cumarone-indene resin, etc.), release agents, electrical conductivity agents, thermal conductivity agents, surface non-adhesive agents, flexibility agents, heat resistance improvers, flame retardants, etc.
• additives can be blended, and one or more commonly used cross-linking agents and cross-linking accelerators different from those described above may be blended.
• the content of the filler such as carbon black is not particularly limited, but is preferably 0 to 300 parts by mass, more preferably 1 to 150 parts by mass, relative to 100 parts by mass of the fluorine-containing elastomer. It is more preferably 2 to 100 parts by mass, and particularly preferably 2 to 75 parts by mass.
• processing aids such as wax is preferably 0 to 10 parts by mass, more preferably 0 to 5 parts by mass, per 100 parts by mass of the fluorine-containing elastomer.
• processing aids, plasticizers and release agents tends to reduce the mechanical properties and sealability of the resulting molded product. need to be adjusted.
• a molded article can be obtained by cross-linking the fluorine-containing elastomer composition. Molded articles can also be obtained by molding and crosslinking the fluorine-containing elastomer composition.
• a fluorine-containing elastomer composition can be molded by a conventionally known method. The method and conditions for molding and crosslinking may be within the range of known methods and conditions for molding and crosslinking to be employed. The order of molding and crosslinking is not limited, and crosslinking may be performed after molding, molding may be performed after crosslinking, or molding and crosslinking may be performed simultaneously.
• molding methods include compression molding, injection molding, injection molding, extrusion molding, and molding using a roto-curing method, but are not limited to these.
• a steam cross-linking method, a cross-linking method by heating, a radiation cross-linking method, or the like can be employed.
• the steam cross-linking method and the cross-linking method by heat are preferable.
• Specific cross-linking conditions which are not limited, are usually within a temperature range of 140 to 250° C. and a cross-linking time of 1 minute to 24 hours.
• Specific cross-linking conditions which are not limited, are usually in the temperature range of 140 to 300° C. and in the range of 30 minutes to 72 hours.
• the resulting molded products can be used as various parts in various fields such as the automobile industry, aircraft industry, and semiconductor industry. Molded products include, for example, sealing materials, sliding members, non-adhesive members, crosslinked rubber molded products described in JP-A-2013-216915, and fluororubber molded products described in JP-A-2019-94430. can be used for
• Examples of usage forms of molded products include various sealing materials and packings such as rings, packings, gaskets, diaphragms, oil seals, and bearing seals.
• As a sealing material it can be used in applications requiring excellent non-adhesiveness and low friction properties. In particular, it can be suitably used for various sealing materials in the automobile industry and the like.
• tubes hoses, rolls, various rubber rolls, flexible joints, rubber plates, coatings, belts, dampers, valves, valve seats, valve bodies, chemical-resistant coating materials, laminating materials, lining materials, etc. can.
• Solid content concentration of aqueous dispersion 1 g of the aqueous dispersion is dried in a blower dryer at 150 ° C. for 180 minutes, and the mass of the heating residue is measured. The mass ratio (% by mass) of the minutes was determined.
• Copolymer composition It was determined by NMR analysis.
• Polymer Adhesion Rate The ratio of the mass of polymer deposits adhering to the polymerization tank after completion of polymerization to the total amount of polymer (fluorine-containing elastomer) after completion of polymerization (adhesion rate to polymerization tank) was determined by the following formula.
• Polymer deposition rate (% by mass) mass of polymer deposit/mass of obtained polymer (including polymer deposit) x 100
• Mass of polymer obtained mass of aqueous dispersion x solid content concentration of aqueous dispersion (% by mass)/100 + mass of polymer deposits.
• the mass of the polymer deposit is the mass after removing moisture contained in the polymer deposit by drying at 120°C.
• Number of particles (number of fluorine-containing elastomer particles in aqueous dispersion) It was calculated by the following formula.
• the average particle size is the average particle size (cumulant average size) of the fluorine-containing elastomer particles in the aqueous dispersion, and is measured by the dynamic light scattering method using ELSZ-1000S (manufactured by Otsuka Electronics Co., Ltd.). , calculated by the cumulant method.
• the number of polymer particles is the number per 1 cc of water, and the specific gravity of all the fluorine-containing elastomers of Examples and Comparative Examples was 1.8.
• Mooney viscosity (ML1+10 (100°C)) The Mooney viscosity was measured according to JIS K 6300-1.2013 at 100° C. using a Mooney viscometer MV2000E manufactured by ALPHA TECHNOLOGIES.
• MH Maximum torque level
• the fluorine-containing elastomer compositions prepared in Examples and Comparative Examples were crosslinked at 160° C. using a rubber vulcanization tester MDRH2030 (manufactured by M&K Co., Ltd.) to determine the crosslinking curve and the maximum torque level (MH). rice field.
• Compression set According to JIS K6262, the compression set of the O-rings produced in Examples and Comparative Examples was measured under conditions of 200° C., 72 hours, and a compression ratio of 25%.
• VdF, TFE and HFP initial monomer were injected so that the internal pressure of the tank was 1.47 MPaG.
• an aqueous polymerization initiator solution prepared by dissolving 0.026 g of ammonium persulfate (APS) in deionized water was pressurized with nitrogen gas to initiate polymerization.
• APS ammonium persulfate
• the polymerization tank was cooled to obtain a fluorine-containing elastomer aqueous dispersion.
• Table 1 shows the solid content concentration, polymer adhesion rate and number of particles of the aqueous dispersion.
• VdF, TFE and HFP initial monomer were injected so that the internal pressure of the tank was 1.47 MPaG.
• an aqueous polymerization initiator solution prepared by dissolving 0.026 g of ammonium persulfate (APS) in deionized water was pressurized with nitrogen gas to initiate polymerization.
• APS ammonium persulfate
• the polymerization tank was cooled to obtain a fluorine-containing elastomer aqueous dispersion.
• Table 1 shows the solid content concentration, polymer adhesion rate and number of particles of the aqueous dispersion.
• VdF, TFE and HFP initial monomer were injected so that the internal pressure of the tank was 1.47 MPaG.
• an aqueous polymerization initiator solution prepared by dissolving 0.026 g of ammonium persulfate (APS) in deionized water was injected with nitrogen gas to initiate polymerization.
• APS ammonium persulfate
• the polymerization tank was cooled to obtain a fluorine-containing elastomer aqueous dispersion.
• Table 1 shows the solid content concentration, polymer adhesion rate and number of particles of the aqueous dispersion.
• VdF, TFE and HFP initial monomer were injected so that the internal pressure of the tank was 1.47 MPaG.
• an aqueous polymerization initiator solution prepared by dissolving 0.026 g of ammonium persulfate (APS) in deionized water was injected with nitrogen gas to initiate polymerization.
• APS ammonium persulfate
• the polymerization tank was cooled to obtain a fluorine-containing elastomer aqueous dispersion.
• Table 1 shows the solid content concentration, polymer adhesion rate and number of particles of the aqueous dispersion.
• VdF, TFE and HFP initial monomer were injected so that the internal pressure of the tank was 1.47 MPaG.
• an aqueous polymerization initiator solution prepared by dissolving 0.026 g of ammonium persulfate (APS) in deionized water was pressurized with nitrogen gas to initiate polymerization.
• APS ammonium persulfate
• the polymerization tank was cooled to obtain a fluorine-containing elastomer aqueous dispersion.
• Table 1 shows the solid content concentration, polymer adhesion rate and number of particles of the aqueous dispersion.
• VdF, TFE and HFP initial monomer were injected so that the internal pressure of the tank was 1.47 MPaG.
• an aqueous polymerization initiator solution prepared by dissolving 0.026 g of ammonium persulfate (APS) in deionized water was pressurized with nitrogen gas to initiate polymerization.
• APS ammonium persulfate
• the polymerization tank was cooled to obtain a fluorine-containing elastomer aqueous dispersion.
• Table 1 shows the solid content concentration, polymer adhesion rate and number of particles of the aqueous dispersion.
• the obtained fluorine-containing elastomer composition was press-crosslinked at 160°C for 10 minutes and oven-crosslinked at 180°C for 4 hours to prepare an O-ring (P24 size).
• Table 1 shows the compression set resistance (CS) of the O-ring.

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• Polymerisation Methods In General (AREA)
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• 2022
  • 2022-06-09 WO PCT/JP2022/023335 patent/WO2022260137A1/ja not_active Ceased
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• 2023
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