Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L27/00—Compositions of homopolymers or 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; Compositions of derivatives of such polymers
  • C08L27/02—Compositions of homopolymers or 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; Compositions of derivatives of such polymers not modified by chemical after-treatment
  • C08L27/12—Compositions of homopolymers or 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; Compositions of derivatives of such polymers not modified by chemical after-treatment containing fluorine atoms
  • C08L27/18—Homopolymers or copolymers or tetrafluoroethene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J3/00—Processes of treating or compounding macromolecular substances
  • C08J3/20—Compounding polymers with additives, e.g. colouring
  • C08J3/205—Compounding polymers with additives, e.g. colouring in the presence of a continuous liquid phase
  • C08J3/21—Compounding polymers with additives, e.g. colouring in the presence of a continuous liquid phase the polymer being premixed with a liquid phase
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J3/00—Processes of treating or compounding macromolecular substances
  • C08J3/24—Crosslinking, e.g. vulcanising, of macromolecules
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
  • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
  • C08L23/10—Homopolymers or copolymers of propene
  • C08L23/14—Copolymers of propene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L27/00—Compositions of homopolymers or 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; Compositions of derivatives of such polymers
  • C08L27/02—Compositions of homopolymers or 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; Compositions of derivatives of such polymers not modified by chemical after-treatment
  • C08L27/12—Compositions of homopolymers or 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; Compositions of derivatives of such polymers not modified by chemical after-treatment containing fluorine atoms
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2205/00—Polymer mixtures characterised by other features
  • C08L2205/02—Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group
  • C08L2205/025—Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure

Definitions

• the present invention relates to a fluoroelastic copolymer composition containing a fluoroelastic copolymer and a fluororesin, a fluororubber composition, and a method for producing these.
• Crosslinked rubber obtained by cross-linking a fluorine-containing elastic copolymer is excellent in heat resistance, chemical resistance, oil resistance, weather resistance, etc., and therefore is a sealing material (for example, O-ring, packing, oil seal). , Gasket) and cushioning material, widely used in the fields of vehicles, ships, aircraft, general machinery, construction, etc.
• Patent Document 1 describes a fluoroelastic copolymer having a unit based on tetrafluoroethylene and a unit based on propylene, an organic peroxide (crosslinking agent), a crosslinking aid and the like.
• a method of cross-linking the containing composition to obtain a cross-linked rubber is disclosed.
• the present invention provides a fluorinated rubber having a hardness that can be used as a sealing material without requiring an additive such as carbon black, a fluorinated elastic copolymer composition capable of easily obtaining the fluorinated rubber, and production thereof. Provide a method.
• the present inventors can obtain a fluororubber having high hardness by mixing the fluoroelastic copolymer water dispersion and the fluororesin water dispersion and then aggregating the fluororubber. They have found that a fluoroelastic copolymer composition can be easily obtained, and have reached the present invention.
• Condition 1 The absolute value of the difference between the pH value of the fluororesin-containing elastic copolymer aqueous dispersion and the pH value of the fluororesin aqueous dispersion is 2.0 or less.
• Condition 2 The pH value of the fluororesin-containing elastic copolymer water dispersion and the pH value of the fluororesin water dispersion are both 7.0 or more.
• [5] The method for producing a fluororesin-containing elastic copolymer composition according to any one of [1] to [3], wherein the volume-based cumulative 50% diameter of the fluororesin contained in the fluororesin aqueous dispersion is 200 to 400 nm. ..
• [6] The method for producing a fluorine-containing elastic copolymer composition according to any one of [1] to [5], wherein a coagulant is added to the aqueous dispersion mixture to cause the aggregation.
• [7] The method for producing a fluorine-containing elastic copolymer composition according to any one of [1] to [5], wherein the aqueous dispersion mixture is frozen to perform the aggregation.
• the fluororesin contains a fluoroelastic copolymer and a fluororesin, and the fluororesin is contained in an amount of 0.5 to 20 parts by mass with respect to 100 parts by mass of the fluoroelastic copolymer, and the fluororesin contains the fluororesin.
• a fluororesin-containing elastic copolymer composition that is dispersed in a copolymer and has an average dispersed particle size of the fluororesin of 30 to 200 nm.
• the ratio of the fluororesin is 0.5 to 20 parts by mass with respect to 100 parts by mass of the component derived from the fluorine-containing elastic copolymer, and the fluororesin is dispersed in the fluororubber.
• the fluororubber according to [12], wherein the fluororesin has an average dispersed particle size of 30 to 200 nm.
• the present invention it is possible to provide a fluorine rubber having excellent hardness and a fluorine-containing elastic copolymer composition capable of easily obtaining the fluorine rubber without requiring an additive such as carbon black, and a method for producing the same.
• the meanings of the terms in the present invention are as follows.
• the "unit” is a general term for an atomic group derived from one molecule of the monomer, which is directly formed by polymerizing the monomer, and an atomic group obtained by chemically converting a part of the atomic group. is there.
• the "unit based on a monomer” is also simply referred to as a “unit” below.
• the numerical range represented by using “-” means a range including the numerical values before and after "-” as the lower limit value and the upper limit value.
• “Rubber” means rubber exhibiting properties as defined by JIS K 6200 (2008) and is distinguished from “resin”.
• Volume-based cumulative 50% diameter is the point where the particle size distribution is measured by the laser diffraction / scattering method, the cumulative curve is obtained with the total volume of the particle population as 100%, and the cumulative volume is 50% on the cumulative curve. Particle size. Hereinafter, it is also referred to as D50.
• the fluorinated elastic copolymer contained in the fluorinated elastic copolymer aqueous dispersion is based on tetrafluoroethylene (hereinafter, also referred to as TFE).
• TFE tetrafluoroethylene
• a copolymer having a unit based on and a unit based on vinylidene fluoride (hereinafter, also referred to as VdF) is preferable.
• the fluoroelastic copolymer of the present invention is a copolymer whose melting point cannot be observed. More precisely, it is a copolymer whose melting point cannot be found because the thermal decomposition temperature is lower than the melting point.
• the fluoroelastic copolymer of the present invention is a copolymer that can be crosslinked. More precisely, it is a copolymer having a cross-linking point, and rubber can be obtained by cross-linking after adding a cross-linking agent or the like.
• the fluoroelastic copolymer of the present invention preferably has a storage elastic modulus G'of 10 to 800 kPa, more preferably 150 to 600 kPa, and even more preferably 200 to 500 kPa.
• Each copolymer is obtained by a general radical polymerization method.
• the radical polymerization method include a living radical polymerization method such as an iodine transfer polymerization method in which iodine is radically polymerized in the presence of elemental iodine or an iodine compound.
• Examples of the copolymer having a TFE unit and a propylene unit (hereinafter, also referred to as P unit) and a method for producing the same include the copolymers described in International Publication No. 2009/11202 and International Publication No. 2017/057512. Will be done.
• Examples of the copolymer having HFP unit and VdF unit and the method for producing the same include the copolymer described in JP-A-06-306180.
• Examples of the copolymer having a TFE unit and a PAVE unit and a method for producing the same include the copolymer described in US Pat. No. 4,305,565 and International Publication No. 2010/082633.
• the copolymer obtained by the production method described in the above document may be dispersed in an aqueous medium and used, and the obtained aqueous dispersion may be used as it is or as appropriate. It may be diluted and used. Above all, it is preferable to use the obtained aqueous dispersion as it is or by appropriately diluting it.
• copolymers can be exemplified as preferable copolymers.
• a copolymer having TFE units and P units, and the total of TFE units and P units is 65 to 100 mol% with respect to all units (hereinafter referred to as TFE-P-based copolymer).
• a copolymer having HFP units and VdF units, and the total of HFP units and VdF units is 50 to 100 mol% with respect to all units (hereinafter referred to as HFP-VdF-based copolymer).
• a copolymer having TFE units and PAVE units, and the total of TFE units and PAVE units is 50 to 100 mol% with respect to all units (hereinafter referred to as TFE-PAVE-based copolymer).
• TFE-P-based copolymer is preferable.
• the total of TFE units and P units is 65 to 100 mol% with respect to all the units of the copolymer, and the molar ratio of TFE units / P units is 30/70 to 70 /.
• a copolymer of 30 is preferred.
• the molar ratio of TFE units / P units is preferably 45/55 to 65/35, more preferably 50/50 to 60/40.
• the TFE-P-based copolymer may contain 0.01 to 5.0% by mass of iodine atoms.
• a unit based on the monomer 1 represented by the following formula (1) (hereinafter referred to as unit 1) is preferable.
• R 1 , R 2 , R 3 , R 5 , R 6 and R 7 are independently hydrogen atoms, fluorine atoms or methyl groups, and R 4 has 1 carbon atom.
• the ratio of unit 1 to all units is preferably 0.05 to 1.5 mol%, more preferably 0.1 to 0.8 mol%, still more preferably 0.15 to 0.6 mol%.
• the copolymer contains TFE units, P units and unit 1, the total of TFE units, P units and unit 1 with respect to all the units of the copolymer is preferably 98 to 100 mol%.
• the molar ratio of TFE units / P units is preferably 30/70 to 70/30, more preferably 45/55 to 65/35, and even more preferably 50/50 to 60/40.
• units other than the TFE unit, the P unit, and the unit 1 include units based on the following monomers.
• Fluorinated olefins monofluoroethylene, trifluoroethylene, trifluoropropylene, pentafluoropropylene, hexafluoropropylene, hexafluoroisobutylene, dichlorodifluoroethylene, vinyl fluoride, perfluorocyclobutene, pentafluorobutylene, heptafluoropentene, nona Fluorohexene, undecafluoroheptene
• Hydrocarbon olefins ethylene, 1-butene, isobutylene, penten Alkene alkyl vinyl ether: methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, cyclohexyl vinyl ether vinyl ester: vinyl acetate, vinyl propionate, caproic acid Vinyl, vinyl caprylate
• the TFE-P-based copolymer preferably contains an iodine atom.
• the iodine atom is preferably 0.01 to 5.0% by mass, more preferably 0.05 to 1.5% by mass, still more preferably 0.1 to 1.0% by mass, based on the total mass of the copolymer. .. Within this range, cross-linking becomes easy while maintaining the rubber physical properties of the TFE-P-based copolymer, which is preferable.
• Examples of the method for introducing an iodine atom into the copolymer include a method using a monomer having an iodine atom as the above-mentioned other monomer and a method using a chain transfer agent having an iodine atom for polymerization.
• a method using a chain transfer agent is preferable because an iodine atom can be introduced into the main chain terminal of the copolymer and the cross-linking site can be easily controlled.
• 1,4-diiodoperfluorobutane 1,2-diiodoperfluoroethane, 1,3-diiodoperfluoropropane, 1,5-diiodoperfluoropentane, 1,6- Diiodoperfluorohexane is mentioned, and 1,4-diiodoperfluorobutane is preferable.
• TFE-P copolymers As commercially available TFE-P copolymers, "Afras 100S”, “Afras 100H”, “Afras 150P”, “Afras 150C”, “Afras 150CS”, “Afras 300S”, “Afras 400E”, “Afras 600S” (The above is manufactured by AGC Inc.) and the like.
• the total of HFP units and VdF units is 50 to 100 mol% with respect to all the units of the copolymer, and the molar ratio of VdF units / HFP units is 60/40 to 95 /.
• the copolymer of 5 is preferable.
• the molar ratio of VdF unit to HFP unit is preferably 70/30 to 90/10, more preferably 75/25 to 85/15.
• the HFP-VdF-based copolymer may contain 0.01 to 5.0% by mass of iodine atoms.
• the TFE unit is preferable.
• the total of HFP units, VdF units and TFE units with respect to all the units of the copolymer is preferably 98 to 100 mol%.
• the molar ratio of VdF unit / TFE unit / HFP unit is preferably 50/5/45 to 65/30/5, more preferably 50/15/35 to 65/20/15.
• units other than the HFP unit, TFE unit, and VdF unit include units based on the following other monomers.
• Other monomers Chlorotrifluoroethylene, trifluoroethylene, vinyl fluoride, ethylene, ethylidene norbornene, vinyl crotate
• the other units are preferably 50 mol% or less, preferably 30 mol% or less. More preferably, 10 mol% or less is further preferable.
• TFE-PAVE-based copolymer a copolymer in which the total of TFE units and PAVE units is 50 to 100 mol% and the molar ratio of TFE units / PAVE units is 20/80 to 80/20 is preferable.
• the molar ratio of TFE unit / PAVE unit is preferably 50/50 to 80/20, more preferably 60/40 to 75/25.
• the TFE-PAVE-based copolymer may contain 0.01 to 5.0% by mass of iodine atoms.
• Examples of PAVE include perfluoro (methyl vinyl ether), perfluoro (ethyl vinyl ether), perfluoro (propyl vinyl ether), perfluoro (methoxyethyl vinyl ether), perfluoro (propoxyethyl vinyl ether), and perfluoro (propoxypropyl vinyl ether).
• units other than the TFE unit and the PAVE unit include the TFE-P-based copolymer system, the units based on the other monomers mentioned in the HFP-VdF-based copolymer, and HFP and VdF. .. With respect to all units, the other units are preferably 50 mol% or less, more preferably 30 mol% or less, still more preferably 10 mol% or less.
• the TFE-PAVE-based copolymer preferably contains an iodine atom.
• the iodine atom is preferably 0.01 to 5.0% by mass, more preferably 0.05 to 1.5% by mass, still more preferably 0.1 to 0.5% by mass, based on the total mass of the copolymer. .. Within this range, cross-linking becomes easy while maintaining the rubber physical properties of the TFE-PAVE-based copolymer, which is preferable.
• the method for introducing an iodine atom into the copolymer and the preferred chain transfer agent are the same as those for the above-mentioned TFE-P-based copolymer.
• TFE-PAVE-based copolymers described above examples include Viton GLT and Viton GFLT (all manufactured by The Chemours Company).
• Fluorine-containing elastic copolymer preferably contains 10 to 40 parts by mass, and more preferably 15 to 35 parts by mass with respect to 100 parts by mass of the fluorine-containing elastic copolymer aqueous dispersion. Within this range, the fluoroelastic copolymer is likely to be uniformly dispersed in the aqueous dispersion, and is easily mixed with the fluororesin aqueous dispersion, and is easily aggregated.
• the D50 of the fluorinated elastic copolymer contained in the fluorinated elastic copolymer water dispersion is preferably 30 to 200 nm, more preferably 50 to 150 nm. Within this range, precipitation is difficult, the fluoroelastic copolymer is easily uniformly dispersed in the aqueous dispersion, and mixing with the fluororesin aqueous dispersion is also easy.
• the pH value of the fluorine-containing elastic copolymer aqueous dispersion is preferably 2.0 to 14.0, more preferably 7.0 to 14.0, further preferably 9.0 to 14.0, and 11.0 to 11.0. 13.0 is particularly preferable.
• the pH value of the fluororesin-containing elastic copolymer aqueous dispersion is in this range, the absolute value of the difference from the pH value of the fluororesin aqueous dispersion is likely to be 2.0 or less. Further, when the pH value of the fluorine-containing elastic copolymer water dispersion is in this range, the crosslinkability of the fluorine rubber is likely to be improved.
• the crosslinkability is improved, various physical properties of fluororubber such as improvement of tensile strength and reduction of compression set are improved.
• the pH value of the aqueous dispersion of the fluoroelastic copolymer is 2.0 to 9.0, it is preferable to raise the pH to a suitable range by using an aqueous sodium hydroxide solution of 5% by mass or less.
• the pH value is 13.0 to 14.0, the pH can be lowered to a suitable range by using an aqueous solution of sodium dihydrogen phosphate of 5% by mass or less.
• a tetrafluoroethylene-based polymer (hereinafter, also referred to as "TFE-based polymer”) is preferable as the fluororesin contained in the fluororesin aqueous dispersion.
• TFE-based polymers include polytetrafluoroethylene (PTFE), TFE and PAVE copolymer (PFA), TFE and HFP copolymer (FEP), TFE and ethylene copolymer (ETFE), or TFE and vinylidene fluoride.
• Copolymer is preferable, and PTFE is particularly preferable.
• PTFE includes a copolymer of a very small amount (for example, 0.5 mol% or less with respect to all units of the copolymer) of comonomer (PAVE, HFP, FAE, etc.) and TFE.
• PFA may contain units based on monomers other than TFE and PAVE. The same applies to the other copolymers described above.
• the TFE-based polymer is preferably a polymer obtained by emulsion polymerization of fluoroolefin in water.
• fluororesin aqueous dispersion an aqueous dispersion in which a polymer obtained by emulsion polymerization of fluoroolefin in water is dispersed as particles in water may be used as it is, and after the powder is recovered from water, it is used as an aqueous medium. It may be dispersed and used.
• the TFE-based polymer may be modified by surface treatment (radiation treatment, electron beam treatment, corona treatment, plasma treatment, etc.). Examples of such a surface treatment method include the methods described in International Publication No. 2018/026012, International Publication No.
• the dispersion of TFE-based polymers is widely available as a commercial product.
• the melting point of the TFE polymer is preferably 280 ° C. or higher, more preferably 300 to 380 ° C., further preferably 310 to 360 ° C., and particularly preferably 320 to 340 ° C.
• the fluororesin is contained in an amount of 1 to 70 parts by mass, and more preferably 5 to 65 parts by mass with respect to 100 parts by mass of the fluororesin aqueous dispersion. Within this range, the fluororesin is likely to be uniformly dispersed in the aqueous dispersion, is easily mixed with the fluoroelastic copolymer aqueous dispersion, and is easily aggregated.
• the D50 of the fluororesin contained in the fluororesin aqueous dispersion is preferably 200 to 400 nm, more preferably 220 to 350 nm. Within this range, precipitation is difficult, the fluororesin is easily uniformly dispersed in the aqueous dispersion, and it is easy to mix with the fluoroelastic copolymer aqueous dispersion.
• the pH value of the fluororesin aqueous dispersion is preferably 7.0 to 14.0, more preferably 9.0 to 12.0.
• the absolute value of the difference from the pH value of the fluororesin-containing elastic copolymer aqueous dispersion is likely to be 2.0 or less.
• the fluororesin is less likely to be locally aggregated, shrinkage deformation of the fluororubber is prevented, and the molding stability of the fluororubber can be improved.
• the pH value of the fluororesin aqueous dispersion is 2.0 to 7.0, it is preferable to raise the pH to a suitable range by using an aqueous ammonia solution of 30% by mass or less.
• the pH value is 12.0 to 14.0, the pH can be lowered to a suitable range by using an aqueous solution of sodium dihydrogen phosphate of 5% by mass or less.
• the absolute value of the difference between the pH value of the fluorinated elastic copolymer aqueous dispersion and the pH value of the fluororesin aqueous dispersion is 2.0 or less. More preferably 1.5 or less.
• the absolute value is in this range, the fluoroelastic copolymer and the fluororesin are difficult to separate, and are uniformly dispersed and easily aggregated.
• the fluororesin is polytetrafluoroethylene, the fluoroelastic copolymer composition is likely to be fibrillated, but it can be made difficult to be fibrillated by adjusting the pH.
• the pH can be adjusted by adding various pH adjusting agents or the like. Further, by adjusting the pH, it is easy to crosslink the composition without adding an acid receiving agent. Further, even if the pH values of both the fluoroelastic copolymer aqueous dispersion and the fluororesin aqueous dispersion are 7.0 or more, each aqueous dispersion is stable and the fluororesin is less likely to be locally aggregated. At the same time, the fluororubber-containing elastic copolymer composition is easily crosslinked, and a fluororubber having excellent crosslinkability can be obtained.
• the content of the fluororesin is adjusted to 100 mass of the fluoroelastic copolymer. It is an aqueous dispersion mixture containing 0.5 to 20 parts by mass, preferably 1 to 10 parts by mass with respect to parts.
• the content of the fluororesin is in this range, it is difficult to cause fibrillation of the fluororesin, and it is easy to increase the hardness when the fluororesin-containing elastic copolymer composition is crosslinked. It is also excellent in mechanical strength and compression set.
• examples of the aggregating method include a method of adding a coagulant to the aqueous dispersion mixture and a method of freezing.
• a known coagulant When a coagulant is added as a coagulation method, a known coagulant can be used.
• Known coagulant, aluminum salts include calcium salts or magnesium salts, specifically, aluminum sulfate and formula M'Al (SO 4) in 2 ⁇ 12H 2 O [wherein, M 'is It is a monovalent cation other than lithium. ]
• Alum, calcium nitrate, magnesium sulfate can be mentioned.
• potassium chloride and sodium chloride which are monovalent cations can also be used.
• Ammonium acetate and ammonium carbonate can also be used as the organic coagulant.
• Nitric acid can also be used as the inorganic acid coagulant.
• the temperature When freezing as a coagulation method, it is preferable to set the temperature to 3 ° C. or more lower than the freezing point of the aqueous dispersion mixture. For example, ⁇ 8 ° C. or lower is preferable, and ⁇ 10 ° C. or lower is more preferable.
• the aggregation time is preferably 0.5 hours or more, more preferably 1 hour or more. When it is cooled below the freezing point and frozen, it can be aggregated without using a coagulant, so it is suitable when the fluorine-containing elastic copolymer composition is used for applications where the metal content is desired to be reduced, such as semiconductor applications. Is.
• the fluoroelastic copolymer composition of the present invention preferably contains 0.5 to 20 parts by mass, preferably 1 to 10 parts by mass of fluororesin with respect to 100 parts by mass of the fluoroelastic copolymer.
• the content of the fluororesin is in this range, it is difficult to cause fibrillation of the fluororesin, and it is easy to increase the hardness when the fluororesin-containing elastic copolymer composition is crosslinked. It also has excellent mechanical properties and compression set.
• the fluororesin is dispersed in the fluororesin-containing elastic copolymer, and the average dispersed particle size of the fluororesin is 30 to 200 nm.
• the average dispersed particle size is preferably 50 to 150 nm. Within this range, the fluororesin is likely to be uniformly dispersed in the fluoroelastic copolymer.
• the average dispersed particle size of the fluororesin in the fluororesin-containing elastic copolymer composition is equivalent to the average dispersed particle size of the fluororesin in the fluororubber after cross-linking.
• fluoroelastic copolymer and the fluororesin contained in the fluoroelastic copolymer composition of the present invention include those described in the above-mentioned method for producing the fluoroelastic copolymer composition of the present invention, which are suitable. The same applies to the above embodiments.
• the fluoroelastic copolymer is preferably TFE-P-based copolymer, and the fluororesin is preferably PTFE.
• additives such as carbon black are essential while maintaining the heat resistance and oil resistance of fluororubber obtained by cross-linking the fluoroelastic copolymers. The hardness can be increased without using.
• the cleaning liquid of the fluoroelastic copolymer composition of the present invention is preferably water or an alkaline aqueous solution.
• the pH value of the alkaline aqueous solution is preferably 10.0 to 14.0, most preferably 12.0 to 14.0.
• the pH value of the cleaning liquid is in this range, the tensile strength and hardness of the fluororubber described later are increased, and the compression set is improved, which is preferable.
• the hardness and compression set can be adjusted by adding additives such as carbon black, silica, and a resin filler having a D50 of 1 ⁇ m or more to the fluoroelastic copolymer composition.
• the amount to be added is preferably 1 to 30 parts by mass, more preferably 1 to 15 parts by mass with respect to the fluoroelastic copolymer.
• PTFE, PFA, FEP, and ETFE listed as TFE-based polymers are preferable, and PTFE, PFA, and FEP are most preferable.
• the D50 of the resin filler is preferably 1 to 50 ⁇ m, more preferably 1 to 20 ⁇ m.
• the D50 of the resin filler is within this range, it is considered that the fluororesin derived from the fluororesin aqueous dispersion and the resin derived from the resin filler are bimodally dispersed, and the crack resistance of the fluororubber described later is improved.
• Additives can also be added to the fluorine-containing elastic copolymer composition.
• Compressive permanent strain can be improved by adding an acid receiving agent such as sodium stearate, calcium stearate, benzyltriphenylphosphonium chloride (BTPPC), 2-ethyl-4-methylimidazole (2E4MZ).
• BTPPC is the most preferable.
• Fluorine rubber is obtained by cross-linking the above-mentioned fluorine-containing elastic copolymer composition.
• a method for cross-linking the fluoroelastic copolymer composition that is, the fluoroelastic copolymer in the fluoroelastic copolymer composition
• a method of cross-linking the fluoroelastic copolymer composition by heating is preferable. ..
• Specific examples of the crosslinking method by heating include heating press crosslinking, steam crosslinking, and hot air crosslinking. From these methods, the fluoroelastic copolymer composition may be appropriately selected in consideration of the shape and use.
• the heating conditions are preferably 100 to 400 ° C. for 1 second to 24 hours.
• the fluorine rubber obtained by heating the fluorine-containing elastic copolymer composition and primary cross-linking may be further heated and secondary cross-linked.
• the heating conditions for the secondary cross-linking are preferably 100 to 300 ° C. for 30 minutes to 48 hours.
• Examples of the cross-linking method other than cross-linking the fluoroelastic copolymer composition by heating include a method of irradiating the fluoroelastic copolymer composition with radiation to cross-link.
• Specific examples of the radiation to be irradiated include electron beams and ultraviolet rays.
• the ratio of the fluororesin contained in the fluororubber is preferably 0.5 to 20 parts by mass, more preferably 1 to 10 parts by mass with respect to 100 parts by mass of the component derived from the fluororubber-containing elastic copolymer. Within this range, the hardness of the fluororubber is high, and the mechanical properties and compression set are excellent.
• the fluororesin contained in the fluororubber is dispersed in the fluororubber, and the average dispersed particle size of the fluororesin is preferably 30 to 200 nm, more preferably 50 to 150 nm. Within this range, the fluororesin is likely to be uniformly dispersed in the fluororubber.
• the molded product of the present invention is excellent in heat resistance, mechanical strength, post-workability, plasma resistance, and gas barrier property. Further, since the finely dispersed fluororesin fine particles do not easily fall off from the elastomer of the matrix, there is little possibility that particles are generated even when used as a sealing component of a semiconductor manufacturing apparatus, for example. Specific applications of the fluororubber molded product of the present invention include semiconductor manufacturing equipment, packings, sealing materials, and the like in various plants such as petrochemicals.
• Examples 1 to 4 are Examples, and Examples 5 to 8 are Comparative Examples.
• [Fluororesin D50 contained in fluororesin water dispersion] D50 was measured using a laser scattering particle size distribution analyzer (LA-920 (product name) manufactured by HORIBA, Ltd.).
• [Fluorine-containing elastic copolymer D50 contained in the aqueous dispersion of fluorine-containing elastic copolymer] D50 was measured by a dynamic light scattering method using a laser zeta potential meter (FPAR-1000 (product name) manufactured by Otsuka Electronics Co., Ltd.).
• FPAR-1000 product name manufactured by Otsuka Electronics Co., Ltd.
• a fluorinated elastic copolymer composition to which a cross-linking agent or the like is added is kneaded with an open roll, and the obtained composition (hereinafter, also referred to as a cross-linking fluorinated elastic copolymer composition) is visually confirmed. If it was transparent, it was judged as ⁇ , and if it was partially whitened, and if streaks were visible, it was judged as ⁇ .
• the crosslinkable fluoroelastic copolymer composition is heat-pressed (primary crosslinked) at 160 ° C. for 20 minutes and then secondarily crosslinked in an oven at 200 ° C. for 4 hours to obtain a 1 mm thick crosslinked rubber sheet.
• Got The obtained crosslinked rubber sheet was punched out with a No. 4 dumbbell to prepare a measurement sample, and the tensile physical properties (tensile strength, elongation) were measured at 25 ° C. according to JIS K6251.
• the Shore A hardness was measured according to JIS K6253.
• TFE was press-fitted until the internal pressure became 1.765 MPa [gauge], and 26.3 g of disuccinic acid peroxide (concentration 80% by mass, the rest was water) was dissolved in 1 liter of warm water at about 70 ° C. and injected. After about 3 minutes, the internal pressure of the autoclave dropped to 1.716 MPa [gauge], so TFE was press-fitted so as to keep the internal pressure at 1.765 MPa [gauge] to proceed with the polymerization. During the polymerization, the EEA was dissolved in warm water and a total of 53 g of the EEA was injected in two portions.
• the autoclave temperature was gradually raised to 72 ° C., the reaction was terminated when the amount of TFE press-fitted reached 22 kg, and the TFE in the autoclave was released to the atmosphere.
• the polymerization time was 105 minutes.
• the paraffin wax solidified on the upper part was removed to obtain a PTFE aqueous emulsion.
• the PTFE concentration in the PTFE aqueous emulsion was about 25.0% by mass, and the EEA concentration was 0.40% by mass with respect to the PTFE mass.
• the D50 of the PTFE particles in the aqueous emulsion was 0.26 ⁇ m.
• the average molecular weight of PTFE was 760,000, and the standard specific gravity of PTFE was 2.21.
• aqueous PTFE emulsion Using 10 kg of the obtained aqueous PTFE emulsion, 2.7% by mass of a nonionic surfactant (Newcol® 1308FA) and ion-exchanged water were dissolved with respect to the mass of PTFE, and the PTFE concentration was 24. A 2% by mass PTFE low-concentration aqueous dispersion was obtained. Next, 5 kg of the obtained PTFE low-concentration aqueous emulsion and 200 g of a strong base type anion exchange resin (PUROLITE (registered trademark) A300, manufactured by Purolite) were placed in a 5 L beaker and stirred at room temperature for 12 hours.
• PUROLITE registered trademark
• A300 a strong base type anion exchange resin
• this aqueous dispersion was filtered through a nylon mesh having a mesh size of 100 and then concentrated by electrophoresis to remove the supernatant.
• the content of PTFE particles was 65% by mass, and the nonionic surfactant was used.
• a concentrated solution (PTFE aqueous dispersion) having a content of 2.0 parts by mass with respect to 100 parts by mass of the PTFE particles was obtained.
• the nonionic surfactant (Newcol® 1308FA) and ion-exchanged water so that the content of the nonionic surfactant is 2.8% by mass with respect to the mass of PTFE. was dissolved.
• Ion-exchanged water was added so that the PTFE concentration was 60.5% by mass to obtain a PTFE aqueous dispersion.
• pH value of the obtained PTFE aqueous dispersion was confirmed with pH test paper, it was 10.0.
• the pH value of the aqueous medium in the reactor at this time was 8.6.
• the anchor blade was rotated at 300 rpm, and a 2.3% by mass aqueous solution of Longarit (hereinafter referred to as a 2.3% by mass aqueous solution of Longarit) whose pH value was adjusted to 13.0 with sodium hydroxide was added to the reactor for polymerization.
• the reaction was initiated.
• a 2.3 mass% aqueous solution of Longarit was continuously added to the reactor using a high pressure pump.
• the internal temperature of the reactor was cooled to 10 ° C., and the polymerization reaction was stopped at normal pressure to obtain an aqueous dispersion of a fluoroelastic copolymer.
• the amount of the Longalit 2.3 mass% aqueous solution added was 61 g.
• the polymerization time was 7 hours.
• the solid content in the latex was 33% by mass, and the D50 of the fluorine-containing elastic copolymer particles was 0.06 ⁇ m.
• Example 1 A 2% by mass aqueous sodium hydroxide solution was added dropwise to the fluorine-containing elastic copolymer aqueous dispersion obtained in Production Example 2, and the pH value was adjusted to 9.0.
• This aqueous dispersion mixture was allowed to stand in a freezer at -22 ° C for 15 hours, freeze-aggregated, washed with water, dried, and the fluororesin fine particles were finely dispersed in the fluororesin-containing elastic copolymer. I got something.
• the storage elastic modulus G'of this fluorine-containing elastic copolymer composition was 348 kPa. 102.5 parts by mass of the obtained fluoroelastic copolymer composition as a cross-linking agent and 1 part by mass of di (2-t-butylperoxyisopropyl) benzene (referred to as P-14 in Table 2) and as a cross-linking accelerator.
• crosslinkable fluoroelastic copolymer composition 3 parts by mass of triallyl isocyanurate (denoted as TAIC in Table 2) was mixed and kneaded with an open roll to obtain a crosslinkable fluoroelastic copolymer composition. This composition was visually confirmed and it was determined that fibrillation had not occurred.
• the crosslinkable fluoroelastic copolymer composition was press-crosslinked at 160 ° C. for 20 minutes and then crosslinked in an oven at 200 ° C. for 4 hours to obtain a crosslinked fluororubber. It was confirmed that this fluororubber had no deformation strain and was in a flat state, and the normal physical properties were measured. Further, an O-ring (P-26) was manufactured under the same crosslinking conditions, and the compression set was measured.
• P-26 O-ring
• Example 2 A fluorine-containing elastic copolymer composition was obtained in the same manner as in Example 1 except that the fluorine-containing elastic copolymer / PTFE was changed to the values shown in Table 1. Further, a crosslinkable fluorinated elastic copolymer composition and fluorinated rubber were obtained in the same manner as in Example 1 except that the values were changed to those shown in Table 2.
• Example 3 A fluorinated elastic copolymer composition was obtained in the same manner as in Example 1 except that the fluorinated elastic copolymer composition was obtained by chemical aggregation. Further, a crosslinkable fluorinated elastic copolymer composition and fluorinated rubber were obtained in the same manner as in Example 1 except that the values were changed to those shown in Table 2.
• a 25% aqueous solution of KCl (coagulant) is prepared so as to have the same mass as the aqueous dispersion mixture, and the aqueous dispersion mixture is dropped into the 25% aqueous solution of KCl to aggregate, washed with water, and dried. Then, a fluorine-containing elastic copolymer composition in which fluorine resin fine particles were finely dispersed in the fluorine-containing elastic copolymer was obtained.
• Example 4 A 2% by mass aqueous sodium hydroxide solution was added dropwise to the aqueous dispersion of the fluoroelastic copolymer obtained in Production Example 2, and the pH value was adjusted to 11.0 in the same manner as in Example 1. A coalesced composition was obtained. Further, a crosslinkable fluorinated elastic copolymer composition and fluorinated rubber were obtained in the same manner as in Example 1 except that the values were changed to those shown in Table 2.
• Example 5 A fluorine-containing elastic copolymer composition was obtained in the same manner as in Example 1 except that the fluorine-containing elastic copolymer / PTFE was changed to the values shown in Table 1. An attempt was made to obtain a crosslinkable fluorine-containing elastic copolymer composition as in Example 1 except that the values were changed to those shown in Table 2, but kneading with an open roll caused severe fibrillation and molding was difficult. Because of this, it was not possible to obtain normal physical properties.
• Example 6 Chemistry of the fluorinated elastic copolymer in the same manner as in Example 3 except that PTFE was not added to the fluorinated elastic copolymer and a 2% aqueous solution of CaCl 2 (coagulant) was used as chemical aggregation. Aggregated.
• a crosslinkable fluorinated elastic copolymer composition and fluorinated rubber were obtained in the same manner as in Example 1 except that the values were changed to those shown in Table 2.
• Example 7 PTFE (Fluon PTFE L169J manufactured by AGC) was added to the fluorine-containing elastic copolymer obtained in Example 6 at the time of kneading with an open roll to obtain a crosslinkable fluorine-containing elastic copolymer composition and fluorine rubber. It was.
• the amount of PTFE is as shown in Table 1.
• Example 8 A fluorinated elastic copolymer composition was obtained in the same manner as in Example 1 except that the pH of the fluorinated elastic copolymer water dispersion obtained in Production Example 2 was not adjusted. An attempt was made to obtain a crosslinkable fluorine-containing elastic copolymer composition as in Example 1 except that the values were changed to those shown in Table 2, but kneading with an open roll caused severe fibrillation and molding was difficult. Because of this, it was not possible to obtain normal physical properties.
• Example 11 When a crosslinkable fluorinated elastic copolymer composition was obtained using the fluorinated elastic copolymer composition obtained in Example 9, 0.2 parts by mass of BTPPC was added as an additive in the same manner as in Example 9. Fluorine rubber was obtained.
• Example 12 Fluororubber was obtained in the same manner as in Example 11 except that the amount of BTPPC to be added was changed to 0.7 parts by mass.
• Example 13 Fluorine rubber was obtained in the same manner as in Example 11 except that the type of additive was changed to 2E4MZ.
• Example 14 When the crosslinkable fluorinated elastic copolymer composition was obtained using the fluorinated elastic copolymer composition obtained in Example 12, 3 parts by mass of a resin filler (PTFE) was further added in the same manner as in Example 12. Fluorine rubber was obtained. When the test piece after the compression set was observed with respect to the obtained fluororubber, no crack was observed in the test piece.
• PTFE resin filler
• Example 15 Fluororubber was obtained in the same manner as in Example 14 except that the resin filler (PTFE) was changed to the resin filler (PFA). When the test piece after the compression set was observed with respect to the obtained fluororubber, no crack was observed in the test piece.
• the reagents and resin fillers used in Examples 11 to 15 are as follows.
• PTFE Benzyltriphenylphosphonium chloride
• 2-Ethyl-4-methylimidazole manufactured by Shikoku Chemicals Corporation
• PTFE AGC's Fluon PTFE L173J (D50: 7.0 ⁇ m)
• Example 1 is partially reprinted with reference to those described in Table 2.
• the average dispersed particle size of the fluororesins of Examples 14 and 15 is not the resin filler but the value of PTFE derived from the PTFE aqueous dispersion of Production Example 1.

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