Ultra-low temperature elastic fluoropolymer composition and process for preparing the same

Abstract

The elastomeric fluoropolymer may be composed of the following monomer units: about 45 mol % to about 65 mol % -CF2-CH2-, about 8 mol % to about 30 mol % -CF2-CF2-, about 4.5 mol % to about 25 mol % -CF2-CF(O-CF3)-, and about 6 mol % to about 20 mol % -CF2-CF(O-CF2-CF2-O-(CF2-O) n In some embodiments, the composition comprises an elastomeric fluoropolymer and at least one additive. In some embodiments, the composition comprises a first elastomeric fluoropolymer and a second elastomeric fluoropolymer blended with the first elastomeric fluoropolymer. The first elastomeric fluoropolymer comprises the following monomer units: about 45 mol % to about 65 mol % -CF2-CH2-, about 8 mol % to about 30 mol % -CF2-CF2-, about 4.5 mol % to about 25 mol % -CF2-CF(O-CF3)-, and about 6 mol % to about 20 mol % -CF2-CF(O-CF2-CF2-O-(CF2-O) n -CF3)-, where n is 1 or 2.

Description

[Technical Field]

[0001] The present invention relates to elastic fluoropolymers and methods for preparing elastic fluoropolymers. More specifically, the present invention relates to ultra-low temperature elastic fluoropolymers and methods for preparing ultra-low temperature elastic fluoropolymers. [Background technology]

[0002] Fluoroelastomers, possessing excellent heat resistance, oil resistance, and chemical resistance, are widely used in sealing materials, containers, and hoses.

[0003] Examples of fluoroelastomers include copolymers having units of vinylidene fluoride (VF2) and units of at least one other copolymerizable fluorine-containing major monomer, such as hexafluoropropylene (HFP), tetrafluoroethylene (TFE), chlorotrifluoroethylene (CTFE), vinyl fluoride (VF), or fluorovinyl ethers such as perfluoro(alkyl vinyl ether) (PAVE). Specific examples of PAVE monomers include perfluoro(methyl vinyl ether), perfluoro(ethyl vinyl ether), and perfluoro(propyl vinyl ether). Other examples of fluoroelastomers include copolymers of tetrafluoroethylene and perfluoro(alkyl vinyl ethers) such as perfluoro(methyl vinyl ether) (PMVE).

[0004] To provide the physical properties required for most end - uses, fluoroelastomers are conventionally cross - linked. One curing system for many end - uses is the combination of an organic peroxide and a polyfunctional unsaturated co - crosslinking agent. The co - crosslinking agent forms crosslinks by reacting with the curing sites on the polymer chains of the fluoroelastomer. An example of a curing site is an iodine atom bonded to a carbon atom on the fluoroelastomer chain.

[0005] U.S. Patent No. 3,692,843, issued September 19, 1972, entitled “Perfluorovinyl Ethers,” discloses compounds (nVE) of the formula CF3 - O - (CF2 - O) n -CF2 - CF2 - O - CF = CF2 [where n is an integer from 1 to 5].

[0006] U.S. Patent No. 5,696,216 to Kruger et al., issued December 9, 1997, entitled “Peroxide crosslinkable fluororubbers, a process for the production thereof and use thereof,” discloses peroxide - crosslinkable fluororubbers prepared from polymerization units of VF2, one or more fluorinated propenes and / or fluorinated methyl vinyl ethers, one or more perfluoro(polyoxyalkyl vinyl ethers) which can be nVE, and optionally TFE. These fluororubbers have a high VF2 content of 65 - 82 mol% and lack the fluid resistance suitable for use in ultra - low temperature seals.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0008] Good fluid resistance and suitable for use at temperatures below -30°C, with a glass transition temperature (T g ), low-temperature properties such as 10% low-temperature elastic recovery (temperature retraction) (TR10), and 70% low-temperature elastic recovery (TR70), etc. The commercial necessity for cryogenic seals having a combination with such low-temperature properties is increasing. At present, no elastic fluoropolymer containing nVE monomer units that exhibits a combination of fluid resistance and low-temperature properties suitable for such industrial applications has been disclosed.

Means for Solving the Problems

[0009] In an exemplary embodiment, the elastic fluoropolymer comprises the following monomer units: about 45 mol% to about 65 mol% of -CF2-CH2-, about 8 mol% to about 30 mol% of -CF2-CF2-, about 4.5 mol% to about 25 mol% of -CF2-CF(O-CF3)-, about 6 mol% to about 20 mol% of -CF2-CF(O-CF2-CF2-O-(CF2-O) n -CF3)- [where n is 1 or 2].

[0010] [[ID=二十]]In another exemplary embodiment, the composition comprises an elastic fluoropolymer and at least one additive. The elastic fluoropolymer comprises the following monomer units: about 45 mol% to about 65 mol% of -CF2-CH2-, about 8 mol% to about 30 mol% of -CF2-CF2-, about 4.5 mol% to about 25 mol% of -CF2-CF(O-CF3)-, about 6 mol% to about 20 mol% of -CF2-CF(O-CF2-CF2-O-(CF2-O) n -CF3)- [where n is 1 or 2].

[0011] In another exemplary embodiment, the composition comprises a first elastic fluoropolymer and a second elastic fluoropolymer blended with the first elastic fluoropolymer. The first elastic fluoropolymer comprises the following monomer units: about 45 mol% to about 65 mol% of -CF2-CH2-, about 8 mol% to about 30 mol% of -CF2-CF2-, about 4.5 mol% to about 25 mol% of -CF2-CF(O-CF3)-, and about 6 mol% to about 20 mol% of -CF2-CF(O-CF2-CF2-O-(CF2-O) n -CF3)-[wherein n is 1 or 2] and includes.

[0012] Other features and advantages of the present invention will become apparent from the following more detailed description of preferred embodiments, which are made in conjunction with the accompanying drawings illustrating the principles of the present invention as an example. [Modes for carrying out the invention]

[0013] Exemplary cryogenic elastic fluoropolymers and methods for preparing cryogenic elastic fluoropolymers are provided. Embodiments of the disclosure are suitable for cryogenic applications and have a glass transition temperature (T) of -30°C or lower, compared to compositions and methods of materials that do not utilize one or more of the features disclosed herein. g ), 10% low-temperature elastic recovery below -30℃ (TR10), 70% low-temperature elastic recovery below -16℃ (TR70), difference in low-temperature elastic recovery below 14℃ (ΔTR), volume swell less than 28% (VS), compression set less than 50% (CS), maximum torque of at least 10 dNm (M H The present invention provides elastic fluoropolymers having a Mooney viscosity in the range of approximately 10 to approximately 100, or a combination thereof.

[0014] When used in this specification, the glass transition temperature (T g) refers to the temperature determined by differential scanning calorimetry (DSC) using a heating rate of 10 °C / min, as defined according to the International Organization for Standardization (ISO) 22768:2006 test protocol.

[0015] As used herein, the temperature at which 10% recovery occurs (TR10) refers to the temperature determined according to the ISO 2921:2005 test protocol.

[0016] As used herein, the temperature at which 70% recovery occurs (TR70) refers to the temperature determined according to the ISO 2921:2005 test protocol.

[0017] As used herein, the difference in low-temperature elastic recovery (ΔTR) refers to the temperature difference between the TR70 temperature and the TR10 temperature, determined according to the ISO 2921:2005 test protocol.

[0018] As used herein, volume swelling (VS) refers to the rate of increase in volume change upon exposure to M-15 fluid at 60 °C for 70 hours, determined according to the ISO 1817:2011 test protocol.

[0019] As used herein, compression set (CS) refers to the rate of change after �0 hours at 200 °C, determined according to the ISO 815-1:2008 test protocol. <00001​​​​​​​ As used herein, Mooney viscosity refers to a parameter measured under conditions of ML 1+10 (121°C) according to ASTM D1646.

[0022] As used herein, ultra-low temperatures refer to temperatures below -30°C.

[0023] When used herein, the molar percentage of the monomer is as further detailed herein. 1 H and 19 This refers to the molar percentage of monomers in a fluoropolymer, determined from a combination of F nuclear magnetic resonance (NMR) spectroscopy data.

[0024] When used herein, the weight percent of iodine or bromine is as further detailed herein. 1 H and 19 This refers to the weight percentage of iodine or bromine in a fluoropolymer, determined from a combination of F NMR spectroscopic data.

[0025] In some embodiments, the ultra-low temperature elastic fluoropolymer is a random tetrapolymer of the following four monomers: a) Vinylidene fluoride (VF2): CF2 = CH2 b) Tetrafluoroethylene (TFE): CF2 = CF2 c) Perfluoromethyl vinyl ether (PMVE): CF2=CF-O-CF3 d)nVE CF2=CF-O-CF2-CF2-O-(CF2-O) n -CF3 e) In the equation, n = 1 or 2.

[0026] In some embodiments, the ultra-low temperature elastic fluoropolymer has a composition containing an amount of VF2 in the range of about 45 mol% to about 65 mol%, alternatively in the range of about 50 mol% to about 65 mol%, alternatively in the range of about 55 mol% to about 65 mol%, alternatively in the range of about 55 mol% to about 60 mol%, or any value, range, or partial range in between.

[0027] In some embodiments, the ultra-low temperature elastic fluoropolymer has a composition containing an amount of TFE in the range of about 8 mol% to about 30 mol%, alternatively in the range of about 10 mol% to about 25 mol%, alternatively in the range of about 10 mol% to about 20 mol%, alternatively in the range of about 15 mol% to about 20 mol%, or any value, range, or partial range in between.

[0028] In some embodiments, the ultra-low temperature elastic fluoropolymer has a composition containing an amount of PMVE in the range of about 4.5 mol% to about 25 mol%, alternatively in the range of about 5 mol% to about 20 mol%, alternatively in the range of about 5 mol% to about 15 mol%, alternatively in the range of about 10 mol% to about 15 mol%, or any value, range, or partial range in between.

[0029] In some embodiments, the ultra-low temperature elastic fluoropolymer has a composition containing an amount of 1VE in the range of about 6 mol% to about 20 mol%, alternatively in the range of about 6 mol% to about 17 mol%, alternatively in the range of about 6 mol% to about 14 mol%, alternatively in the range of about 10 mol% to about 14 mol%, or any value, range, or partial range between these.

[0030] In some embodiments, the ultra-low temperature elastic fluoropolymer has a composition containing an amount of 2VE in the range of about 6 mol% to about 20 mol%, alternatively in the range of about 6 mol% to about 17 mol%, alternatively in the range of about 6 mol% to about 14 mol%, alternatively in the range of about 10 mol% to about 14 mol%, or any value, range, or partial range between these.

[0031] In some embodiments, the ultra-low temperature elastic fluoropolymer has a composition of about 45 mol% to about 65 mol% VF2, about 8 mol% to about 30 mol% TFE, about 4.5 mol% to about 25 mol% PMVE, and about 6 mol% to about 20 mol% 1VE.

[0032] In some embodiments, the ultra-low temperature elastic fluoropolymer has a composition of about 45 mol% to about 65 mol% VF2, about 8 mol% to about 30 mol% TFE, about 4.5 mol% to about 25 mol% PMVE, and about 6 mol% to about 20 mol% 2VE.

[0033] In some embodiments, the ultra-low temperature elastic fluoropolymer has a Mooney viscosity in the range of about 10 to about 100, alternatively in the range of about 20 to about 70, alternatively in the range of about 30 to about 60, or any value, range, or partial range in between.

[0034] In some embodiments, the cryogenic elastic fluoropolymer further comprises iodine or bromine bonded to carbon atoms of the fluoropolymer to provide curing sites. In some embodiments, the iodine or bromine is present in the fluoropolymer in an amount ranging from about 0.05% to about 0.4% by weight, alternatively from about 0.1% to about 0.35% by weight, alternatively from about 0.2% to about 0.35% by weight, alternatively from about 0.25% to about 0.3% by weight, or any value, range, or partial range between these, relative to the weight of the fluoropolymer.

[0035] Iodine-curable or bromine-curable moieties bonded to the terminal carbons of an elastic fluoropolymer may be provided by using an iodine-containing or bromine-containing chain transfer agent, such as a diiodoperfluoro compound, as described in the polymerization process below. Iodine-curable or bromine-curable moieties along the polymer may also be provided by incorporating an iodine-containing or bromine-containing olefin monomer into the fluoropolymer, for example, by iodotetrafluorobutene, as described in the process below. Iodine-curable moieties are preferred over bromine-curable moieties in relation to the implementation of this embodiment.

[0036] In some embodiments, a semi-batch emulsion polymerization process for preparing an elastic fluoropolymer includes pre-emulsifying nVE liquid monomers in a container. The process also includes supplying TFE gaseous monomers, VF2 gaseous monomers, and PMVE gaseous monomers at polymerization temperature and pressurizing the container to polymerization pressure. The process also includes adding an initiator. The process further includes forming a tetrapolymer from the nVE liquid monomers, TFE gaseous monomers, VF2 gaseous monomers, and PMVE gaseous monomers while maintaining polymerization pressure by continuously supplying TFE gaseous monomers, VF2 gaseous monomers, and PMVE gaseous monomers at polymerization temperature.

[0037] In some embodiments, the ultra-low temperature elastic fluoropolymer is formed by a process comprising: introducing a pre-emulsified nVE liquid monomer into a container; copolymerizing it with TFE, VF2, and PMVE comonomers in the container; stopping the polymerization; removing unreacted liquid nVE monomer by heating to about 70°C to about 100°C and sparging the gas; coagulation; washing the isolated crumbs; and drying the isolated crumb polymer.

[0038] In some embodiments, the ultra-low temperature elastic fluoropolymers are prepared by a semi-batch emulsion polymerization process. In some embodiments, polymerization is carried out in a well-stirred reaction vessel at a temperature in the range of about 0°C to about 50°C, alternatively in the range of about 30°C to about 40°C, alternatively in the range of about 34°C to about 37°C, alternatively in the range of about 35°C, or any value, range, or partial range in between. In some embodiments, the process involves emulsifying nVE in a reactor with an aqueous solution containing a fluorinated surfactant. During emulsification, an aqueous solution of disodium hydrogen phosphate heptahydrate is supplied separately into the reactor. The reactor is then heated to the polymerization temperature and subsequently pressurized with a mixture of gas monomers VF2, TFE, and PMVE.

[0039] In some embodiments, the process then involves the sequential addition of an aqueous solution of sodium pyrosulfite, followed by an aqueous solution of ammonium persulfate, during polymerization. The gas monomer mixture is supplied to the reactor to maintain a constant pressure throughout the polymerization, in the range of about 100 psig to about 300 psig, alternatively in the range of about 120 psig to about 200 psig, alternatively in the range of about 140 psig to about 160 psig, alternatively in the range of about 150 psig, or any value, range, or subrange in between. After a predetermined amount of the gas monomer mixture has been supplied, a mixture of the diiodoperfluoro compounds 1,4-diiodoperfluorobutane, 1,6-diiodoperfluorohexane, 1,8-diiodoperfluorooctane, and 1,10-diiodoperfluorodecane is added to the reactor. After an additional predetermined amount of the gas monomer mixture has been added, iodotetrafluorobutene is also supplied sequentially. After a predetermined amount of gas monomer has been supplied to the reactor for a specified time and in total, the addition of monomer is stopped and the reactor is purged of any residual gaseous monomer(s). The reaction is preferably purged with VF2, but alternative purging gases such as nitrogen or propane may be used.

[0040] Because the polymerization temperature is reduced, thermal initiators can be included, but this is less practical, and redox initiator systems are generally preferred. The elastic fluoropolymers of this disclosure are generally prepared by free radical emulsion polymerization or suspension polymerization. The polymerization initiator may be any conventional peroxide initiator used in emulsion polymerization. Polymerization initiators may include, but are not limited to, inorganic and organic peroxides. Suitable inorganic peroxides may include, but are not limited to, peroxydisulfates, potassium persulfate, or ammonium persulfate. Suitable organic peroxides may include, but are not limited to, hydroperoxides, hydrogen peroxide, benzoyl peroxide, or tert-butyl hydroperoxide. In the case of redox-type initiation, a reducing agent is present in addition to the peroxide. The reducing agent may be any conventional organic or inorganic reducing agent. Suitable inorganic reducing agents may include, but are not limited to, sodium sulfite, sodium bisulfite, or sodium pyrosulfite. Suitable organic reducing agents may include, but are not limited to, ascorbic acid, oxalic acid, or sulfinic acid.

[0041] In some embodiments, the process includes heating the reactor to about 90°C and sparging the gas to remove unreacted nVE. The resulting fluoroelastomer latex is solidified by adding an aqueous solution of aluminum potassium sulfate, and the resulting elastic fluoropolymer is washed with deionized water. The polymer crumb may then be dried at about 80°C.

[0042] In some embodiments, the resulting ultra-low temperature elastic fluoropolymer is isolated, filtered, washed, and dried using conventional techniques used in the elastic fluoropolymer manufacturing industry.

[0043] In some embodiments, the cryogenic elastic fluoropolymer includes bromine-curable or iodine-curable moieties and is peroxide-curable. In some embodiments, the peroxide-curable composition includes the cryogenic elastic fluoropolymer, an organic peroxide, and a co-crosslinking agent. In some embodiments, the peroxide-curable composition also includes an acid acceptor, such as a divalent metal hydroxide, a divalent metal oxide, a strongly basic organic amine having a pKa greater than 10, or a combination thereof. Suitable strongly basic organic amines include, but are not limited to, 1,8-bis(dimethylamino)naphthalene. Suitable divalent metal oxides and hydroxides include, but are not limited to, CaO, Ca(OH)2, Bi2O3, and MgO.

[0044] Suitable organic peroxides include 1,1-bis(t-butylperoxy)-3,5,5-trimethylcyclohexane, 1,1-bis(t-butylperoxy)cyclohexane, 2,2-bis(t-butylperoxy)octane, 4,4-bis(t-butylperoxy)n-butyl valerate, 2,2-bis(t-butylperoxy)butane, 2,5-dimethylhexane-2,5-dihydroxyperoxide, di-t-butylperoxide, t-butylcumylperoxide, and dicumylperoxide. Examples of organic peroxides include, but are not limited to, α,α'-bis(t-butylperoxy-m-isopropyl)benzene, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-dimethyl-2,5-di(t-butylperoxy)hexene-3, benzoyl peroxide, t-butylperoxybenzene, 2,5-dimethyl-2,5-di(benzoylperoxy)-hexane, t-butylperoxymaleic acid, and t-butylperoxyisopropyl carbonate. Preferred examples of organic peroxides include 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, dicumyl peroxide, or α,α'-bis(t-butylperoxy-m-isopropyl)benzene. In some embodiments, the amount of organic peroxide is in the range of 0.05% to 5% by weight, or alternatively, 0.1% to 3% by weight, based on the weight of the ultra-low temperature elastic fluoropolymer. The presence of organic peroxides in amounts less than 0.05% by weight may result in insufficient curing speed and potentially cause poor mold release; therefore, this particular range is selected. On the other hand, if organic peroxides are present in amounts exceeding 5% by weight, the compression set of the cured polymer may become unacceptably high. Furthermore, organic peroxides can be used alone or in combination of two or more types.

[0045] Examples of cocrosslinking agents used in peroxide-curable compositions include polyfunctional unsaturated compounds such as trialyl cyanurate, trimethyryl isocyanurate, trialyl isocyanurate, trimethyryl isocyanurate, triacrylic formal, trialyl trimellitate, N,N'-m-phenylenebismaleimide, diallyl phthalate, tetraallyl terephthalamide, tri(diallylamine)-s-triazine, and trialyl phosphite, for example, CH2=CH(C n F 2n+1 Examples of bis-olefins include, but are not limited to, )-CH=CH2 [wherein n=4, 6, or 8], or N,N-diallylcrylamide. In some embodiments, the amount of cocrosslinking agent is in the range of about 0.1% to about 10% by weight, or alternatively, about 0.2% to about 6% by weight, based on the weight of the ultra-low temperature elastic fluoropolymer. This particular concentration range is selected because if the amount of cocrosslinking agent is less than about 0.1% by weight, the crosslinking density of the cured polymer may be unacceptable. On the other hand, if the amount of cocrosslinking agent is greater than about 10% by weight, blooming may occur on the surface during molding, resulting in poor release properties. Unsaturated compounds can be used alone or in combination of two or more.

[0046] In some embodiments, the composition containing the ultra-low temperature elastic fluoropolymer includes one or more additives. Suitable additives include, but are not limited to, one or more fillers such as carbon black, Austin black, graphite, thermoplastic fluoropolymer powder, silica, clay, diatomaceous earth, talc, wollastonite, calcium carbonate, calcium silicate, calcium fluoride, or barium sulfate; one or more processing aids such as higher fatty acid esters, calcium fatty acid salts, fatty acid amides (e.g., erucamide), low molecular weight polyethylene, silicone oil, silicone grease, stearic acid, sodium stearate, calcium stearate, magnesium stearate, aluminum stearate, or zinc stearate; and / or one or more colorants such as titanium white or red iron. In some embodiments, the amount of filler is in the range of about 0.1% to about 100% by weight, or alternatively, about 1% to about 60% by weight, based on the weight of the ultra-low temperature elastic fluoropolymer. A range is chosen because if the filler is present in an amount of less than about 0.1% by weight, it may have little or no effect, while if more than about 100% by weight of filler is used, elasticity may be sacrificed. In some embodiments, the amount of processing aid is less than about 10% by weight, or alternatively less than about 5% by weight, based on the weight of the ultra-low temperature elastic fluoropolymer. If the amount used exceeds the limit, heat resistance may be adversely affected. In some embodiments, the amount of colorant is less than about 50% by weight, or alternatively less than about 30% by weight, based on the weight of the ultra-low temperature elastic fluoropolymer. If more than about 50% by weight of colorant is used, compression set may deteriorate.

[0047] In some embodiments, a cryogenic elastic fluoropolymer, an organic peroxide, a co-crosslinking agent, and optional additives are incorporated into the peroxide-curable composition by an internal mixer or rubber mill. The resulting peroxide-curable composition can then be molded (e.g., by die molding or extrusion) and cured. In some embodiments, curing is carried out at a temperature in the range of about 150°C to about 200°C for a period of about 1 minute to about 60 minutes. Conventional rubber curing presses, die molds, extruders, etc., with suitable heating and curing capabilities can be used. Furthermore, for optimal physical properties and dimensional stability, the die-molded or extruded composition may undergo a post-curing operation, generally in an air atmosphere, where it is heated in a furnace or the like for an additional period of about 1 to about 48 hours at a temperature in the range of about 180°C to about 275°C.

[0048] The monomer and iodine content values ​​in the elastic fluoropolymer are determined based on the following NMR procedure.

[0049] Tetramethylsilane (TMS) and 1,3,5-tris(trifluoromethyl)benzene (TFMB) are, respectively 1 H chemical shift reference and 1 H / 19 For fluorine quantification, 60-70 mg of the polymer is dissolved overnight in 0.7 mL of acetone-d6 (Cambridge Isotope Laboratories, 99.9% D), which is added to prepare the elastic fluoropolymer sample for NMR analysis in a 5 mm NMR tube (Wilmad 528-PP). TFMB-derived 1 H and 19 F resonances appear at approximately 8.4 ppm and -64 ppm, respectively, and their 1:3 integration ratio is used to analyze the sample. 1 H and 19 Scaling the F NMR spectrum.

[0050] Sample 1The 1H NMR spectrum was acquired at 25°C using a Bruker NEO 600 MHz NMR spectrometer equipped with a 5 mm QCI H / FC / ND cryoprobe. 1 The H spectrum is acquired using a 90° pulse, a 3.5-second acquisition time, a spectral width of 14 ppm, a 45-second repetition time, and 64 scans. The FID is zero-filled to 131072 points, and an exponential linewidth expansion of 0.24 Hz is applied before the Fourier transform. Solvent blanks (containing acetone-d6, TMS, and TFMB) 1 Obtain the H spectrum under the same conditions.

[0051] Sample 19 The 1F NMR spectrum was acquired at 25°C using a Bruker NEO 600 MHz NMR spectrometer equipped with a 5 mm QCI H / FC / ND cryoprobe specially constructed for low fluorine background. 19 The F spectrum is acquired using a 30° pulse, a 2.5-second acquisition time, a spectral width of 185 ppm, a 45-second repetition time, and 128 scans (probe S / N ratio is, 19 (F is 4000:1). The FID is zero-filled up to 524288 points, and an exponential linewidth expansion of 0.33 Hz is applied before the Fourier transform. 19 The fluorine chemical shift is reported for the TFMB signal at -64 ppm.

[0052] The bulk composition of the elastic fluoropolymer is as follows: 19 F and 1 Determined from the integration of the 1H NMR spectrum: 600MHz (564.7MHz) 19 In F), the OCF3 signal of PMVE and the OCF2OCF3 signal of 1VE are, 19In the F spectrum, the molecules are baseline-separated and integrated without overlap. The ratio (on a molar basis) of these two monomers is determined by dividing the integral of OCF3 of PMVE at -54 ppm by 3, and the sum of the integrals of OCF2OCF3 of 1VE at -55 ppm and -58 ppm by 5.

[0053] TFMB 1 H / 19 Using F resonance, 1 H / 19 By uniformly scaling the F spectrum, the amount of VF2 is 1 The concentration is determined by integrating the 4.2 ppm to 1.8 ppm region of the H spectrum, subtracting the concentrations of water and acetone-d6 measured from the solvent blank, and then dividing by 2.

[0054] Next, the amount of TFE is between -80 ppm and -150 ppm. 19 From the integration in the F NMR region, it was determined that the other three monomers are responsible. 19 It is determined by subtracting the F area and dividing by 4. Then, using the normalized molar ratio of each monomer, the bulk composition of the elastic fluoropolymer can be calculated in mole percent and converted to weight percent.

[0055] The proton signal originating from the CF2CH2I terminal is approximately 18 Hz. 3 J (FH) As an aggregate of triple lines having, elastic fluoropolymer 1 It appears in the 4.0 ppm to 3.8 ppm region of the 1H NMR spectrum. The triple line center on the high-field side at 3.8 ppm is due to the CF2CH2OH terminal, and these signals are not included in the quantification of the CF2CH2I terminal. If there is any doubt, standard 1 H- 13 C HSQC NMR experiment revealed that CF2CH2OH methylene (at 65 ppm) 13 C) CF2CH2I methylene (at -3 ppm) 13 Distinguish it from C).

[0056] 4.0 ppm to 3.8 ppm 1 In the 1H NMR region, the methylene signal of CF2CH2I is in the main region VF2. 1 Because it appears in the tailing region of the 1H NMR resonance, it is integrated with strict attention to the slope and bias. 1 H / 19 TFMB for uniformly scaling the F spectrum 1 H / 19 Using F resonance, the amount of CF2CH2I terminals in a polymer sample is determined by dividing the integral of CF2CH2I by 2 and calculating the ratio of CF2CH2I terminals in the bulk composition as a mole percent.

[0057] The weight percentage of iodine in the elastic fluoropolymer derived from the CF2CH2I terminus is calculated by converting the molar percentage of the CF2CH2I terminus to the weight percentage of the CF2CH2I terminus, and then multiplying by the weight percentage of iodine in CF2CH2I, or 0.665. A similar procedure can be used to determine the bromine content when the cured site is a bromine-cured site rather than an iodine-cured site. Insufficient resolution 1 For elastic fluoropolymer samples with 1H NMR spectra, the iodine content in the sample can be measured using alternative methods such as X-ray fluorescence (XRF).

[0058] In some embodiments, the ultra-low temperature elastic fluoropolymer is blended with a second elastic fluoropolymer. The second elastic fluoropolymer may be a perfluoropolymer. In some embodiments, the second elastic fluoropolymer is a commercially available elastic fluoropolymer having physical properties that are less suitable for ultra-low temperature use than the elastic fluoropolymer used alone. For example, in some embodiments, the second elastic fluoropolymer is blended with a second elastic fluoropolymer. g T is above approximately -30°C, alternatively above approximately -25°C, alternatively above approximately -20°C, or any value, range, or partial range in between. In some embodiments, the T of the second elastic fluoropolymerg This is the T of ultra-low temperature elastic fluoropolymers. g It is 5°C higher than, alternatively 10°C, alternatively 15°C, alternatively 20°C, alternatively 25°C, alternatively 30°C, or any value, range, or subrange in between. In some embodiments, the second elastic fluoropolymer is a terpolymer of VF2, TFE, and PMVE. In some embodiments, the relative amount of the polymer is selected to result in a predetermined physical parameter, such as a predetermined glass transition temperature. In some embodiments, the blend has a single glass transition temperature.

[0059] The ultra-low temperature elastic fluoropolymer can be blended with the second elastic fluoropolymer in any relative amount, such as, for example, in the range of about 20% to about 95%, alternatively in the range of about 60% to about 90%, alternatively in the range of about 60% to about 80%, alternatively in the range of about 60% to about 75%, or any value, range, or partial range in between, based on the total weight of the two polymers.

[0060] Ultra-low temperature elastic fluoropolymers can be useful in a variety of applications.

[0061] In some embodiments, ultra-low temperature elastic fluoropolymers can find useful applications in sealing materials, wire coatings, containers, tubes, laminates, and hoses. In some embodiments, ultra-low temperature elastic fluoropolymers provide reliable seals at operating temperatures ranging from about -60°C to about 200°C.

[0062] In some embodiments, ultra-low temperature elastic fluoropolymers can be used in O-rings and shaft seals.

[0063] In some embodiments, ultra-low temperature elastic fluoropolymers can be used in automotive seals.

[0064] In some embodiments, ultra-low temperature elastic fluoropolymers can be used in gas processing plants.

[0065] In some embodiments, ultra-low temperature elastic fluoropolymers can be used in petroleum refineries. [Examples]

[0066] The present invention will be further illustrated by the following embodiments, but will not be limited thereto.

[0067] Example 1. Formation of Example 1 of the present invention Example 1 of the present invention is prepared by a semi-batch emulsion polymerization process, carried out at 35°C in a well-stirred 40 L reaction vessel. 4167 g of 1VE is added to 97.8 g of the fluorinated surfactant C6F, available under the trademark name Capstone® FS-10 (The Chemours Company, Wilmington, DE). 13 The mixture was emulsified in a reactor containing 23 L of aqueous solution of -CH2-CH2-SO3H. During emulsification, water and 2 L of a solution of 141 g of disodium hydrogen phosphate heptahydrate were separately supplied to the reactor. The reactor was heated to 35°C and then pressurized to 150 psig with a gas monomer mixture of 62.3 wt% VF2, 15.7 wt% TFE, and 22.0 wt% PMVE. 39.6 mL of an aqueous solution of 2 wt% sodium pyrosulfite was added continuously at a rate of 10.5 mL / hour, followed by 47.5 mL of an aqueous solution of 2 wt% ammonium persulfite at a rate of 12.7 mL / hour. A gas monomer mixture of 60 wt% VF2, 22 wt% TFE, and 18 wt% PMVE was supplied to the reactor, and a pressure of 150 psig was maintained throughout the polymerization. After supplying 20 g of the gas monomer mixture, 7.0 mL of a mixture containing 45.9 mol% 1,4-diiodoperfluorobutane, 41.1 mol% 1,6-diiodoperfluorohexane, 9.4 mol% 1,8-diiodoperfluorooctane, and 3.3 mol% 1,10-diiodoperfluorodecane was added to the reactor. After adding 848 g of the gas monomer mixture, iodotetrafluorobutene was also continuously supplied at a rate of 14.9 mL per 3000 g of the supplied gas monomer mixture.

[0068] After 9.2 hours, and after a total of 4167 g of gas monomers had been supplied to the reactor, monomer addition was stopped and the reactor was purged of residual gaseous monomers. The reactor was then heated to 90°C and sparged with an inert gas (nitrogen) to remove unreacted 1VE. The resulting fluoroelastomer latex was solidified by the addition of an aqueous solution of aluminum potassium sulfate, and the resulting fluoroelastomer was washed with deionized water. The polymer crumb was dried at 80°C for 8 hours. The obtained Example 1 of the present invention was analyzed by NMR spectroscopy as described above, and it was determined that it contained a polymer composition of 61.1 mol% VF2, 17.8 mol% TFE, 7.5 mol% PMVE, and 13.6 mol% 1VE, as well as 0.18 wt% iodine. Example 1 of the present invention was an amorphous fluoroelastomer having a glass transition temperature of -45°C, as determined by differential scanning calorimetry (DSC, heating mode, 10°C / min, transition inflection point).

[0069] Example 2. Comparative Example Four comparative examples were formed and evaluated. The comparative examples were formed using the process of Example 1 described above, except that different ratios of monomers were used. The compositions of these comparative examples, determined by NMR spectroscopy as described above after the formation of the compositions, are shown in Table 1.

[0070] [Table 1]

[0071] Elastic fluoropolymer is processed in a two-roll mill using the following components (by weight, per 100 parts of polymer): 30 parts of carbon black (medium thermal grade) commercially available from Orion Engineered Carbons LLC (Kingwood, TX) under the trademark "Corax® N990"; 4.2 parts of 1,3,5-trialyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione (72 wt%) on a silica support commercially available from Natrochem Inc. (Savannah, GA) under the trademark "TAIC DLC®-A"; 2 parts of 2,5-dimethyl-2,5-di-(tert-butylperoxy)hexane (45 wt%) on a calcium carbonate / silica support commercially available from Vanderbilt Chemicals LLC (Norwalk, CT) under the trademark "Varox® DBPH-50"; and "Zoco Grade" from Zochem LLC (Dickson, TN). Three parts of commercially available zinc oxide (102) and 0.7 parts of a blend of a fatty acid derivative containing less than 25% octadecylamine and wax, commercially available from Struktol Company of America (Stow, OH) under the trademark name "Struktol® HT 290," were prepared and press-cured at 177°C for a time equal to t90+10 minutes to form O-rings and slabs, and then post-cured in an air-circulating furnace at 230°C for 4 hours. For each of the four comparative examples, physical property parameters were measured and recorded to evaluate their suitability for ultra-low temperature applications. The results of the evaluation of these comparative examples are shown in Table 2.

[0072] [Table 2]

[0073] Comparative Example 1 had a volume swelling of 29.5%, exceeding the 28% threshold, and a compression set of 59%, exceeding the 50% threshold. Comparative Example 2 had a volume swelling of 31.0%, exceeding the 28% threshold. Comparative Example 3 had a low-temperature elastic recovery difference of 15°C, exceeding the 14°C threshold. Comparative Example 4 had a low-temperature elastic recovery of 10% at -26°C, exceeding the -30°C threshold, a low-temperature elastic recovery of 70% at 0.0°C, exceeding the -16°C threshold, and a low-temperature elastic recovery difference of 26°C, exceeding the 14°C threshold.

[0074] Each of the comparative examples had a composition in which at least one monomer was outside the ranges of 45-65 mol% for VF2, 8-30 mol% for TFE, 4.5-25 mol% for PMVE, and 6-20 mol% for 1VE.

[0075] Example 3. Example of the present invention In addition to Example 1 of the present invention, eight other examples of the present invention were formed and evaluated. These examples were formed by the same process as Example 1, except that different ratios of monomers were used. The compositions of these nine examples of the present invention, determined by NMR spectroscopy as described above after the formation of the compositions, are shown in Table 3.

[0076] [Table 3]

[0077] The elastic fluoropolymer of the present invention was prepared in a two-roll mill using the same method and the same amounts of other components as the elastic fluoropolymer of the comparative example. For each of the nine examples of the present invention, physical property parameters were measured and recorded to evaluate the suitability of those examples of the present invention for ultra-low temperature applications. The results of the evaluation of these examples of the present invention are shown in Table 4.

[0078] [Table 4]

[0079] Each of the nine embodiments of the present invention had a glass transition temperature, 10% low-temperature elastic recovery, 70% low-temperature elastic recovery, low-temperature elastic recovery difference, volume swelling, compression set, and maximum torque within a predetermined range for use as an ultra-low temperature elastic fluoropolymer.

[0080] Each of the nine examples of the present invention had a composition ranging from 45 to 65 mol% VF2, 10 to 30 mol% TFE, 4.5 to 25 mol% PMVE, and 6 to 20 mol% 1VE.

[0081] Example 4. Blend Example 9 of the present invention was blended with a commercially available fluoroelastomer in various ratios to evaluate the suitability of such blends for low temperature and / or ultra-low temperature applications. The commercially available fluoroelastomer was Viton® GFLT-200S (The Chemours Company, Wilmington, DE). Viton® GFLT-200S is suitable for applications at -23°C. g This is a terpolymer of VF2, TFE, and PMVE having [specific properties].

[0082] The tested blends contained 100% by weight, 75% by weight, 63% by weight, and 50% by weight of Example 9 of the present invention. The elastic fluoropolymer is processed in a two-roll mill using the following components (parts by weight per 100 parts of polymer): 30 parts carbon black (medium thermal grade) commercially available from Cancarb Limited (Medicine Hat, Alberta, Canada) as "MT Thermax Floform N 990", 3 parts 1,3,5-trialyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione commercially available from The Chemours Company (Wilmington, DE) as "Rubber chem Diak no 7", 2.2 parts 2,2,5-dimethyl-2,5-di-(tert-butylperoxy)hexane (45 wt%) on a calcium carbonate / silica support commercially available from Arkema (Colombes, France) under the trademark name "Luperox® 101 XL 45", and zinc oxide (ReagentPlus 99.9%) commercially available from Sigma-Aldrich Corp. (St. Louis, MO). The mixture was prepared using 3 parts (5 micrometers) and 0.7 parts of Struktol® HT 290, a blend of a fatty acid derivative containing less than 25% octadecylamine and wax. The mixture was press-cured at 180°C for a time equal to t90+10 minutes to form O-rings and slabs, and then post-cured in an air-circulating furnace at 230°C for 4 hours. For each blend, physical property parameters were measured and recorded to evaluate their suitability for ultra-low temperature applications. The results of the evaluation of these blends are shown in Table 5.

[0083] [Table 5]

[0084] Each of the blends, with the exception of the 50:50 blend, had a single glass transition temperature. As shown in Table 5, both the TR10 and TR70 values ​​decreased with decreasing content in Example 9 of the present invention.

[0085] Each blend was also tested at a temperature of 23°C for tensile strength (TS), elongation at break (EAB), and modulus of elasticity (M@100%) according to the ISO 37:2005 Cor 1 2008 test protocol. As shown in Table 5, the measured tensile strengths ranged from 13.5 to 16.0 MPa and increased with decreasing content of Example 9 of the Invention. The measured elongation at break increased from 227% to 239% to 242% with decreasing content of Example 9 of the Invention, and then decreased to 217% for the 50:50 blend. The measured modulus of elasticity values ​​ranged from 2.9 to 4.0 MPa and increased with decreasing content of Example 9 of the Invention.

[0086] The low-temperature compression set of the blends was measured under two different conditions: after 24 hours at -20°C (24 / -20) and after 24 hours at -30°C (24 / -30). The results of the evaluation of these blends are shown in Table 6.

[0087] [Table 6]

[0088] Despite containing many components of commercially available fluoroelastomers, the blend exhibited surprisingly good low-temperature properties, as evidenced by its low TR and low-temperature compression set data.

[0089] While the present invention has been described with reference to preferred embodiments, those skilled in the art will understand that various modifications can be made without departing from the scope of the invention, and that equivalents can be used in place of certain elements. In addition, many modifications can be made without departing from the essential scope of the invention to adapt the teachings of the invention to specific situations or materials. Therefore, the present invention is not limited to the specific embodiments disclosed as the best mode intended to carry out the invention, and the present invention is intended to include all embodiments that fall within the scope of the appended claims.

Claims

1. An elastic fluoropolymer, comprising the following monomer units: 45 mol% to 65 mol% -CF2-CH2- and 8 mol% to 30 mol% -CF2-CF2- and 4.5 mol% to 25 mol% -CF2-CF(O-CF3)- and, 6 mol% to 20 mol% -CF 2 -CF (O-CF) 2 -CF 2 -O-(CF 2 -O) n -CF 3 An elastic fluoropolymer comprising ) - [wherein n is 1 or 2].

2. The elastic fluoropolymer according to claim 1, wherein the elastic fluoropolymer is a random tetrapolymer.

3. The elastic fluoropolymer according to claim 1 or 2, wherein n is 1.

4. The elastic fluoropolymer according to claim 1 or 2, wherein n is 2.

5. The elastic fluoropolymer according to claim 1, further comprising an iodine-cured portion or a bromine-cured portion.

6. The elastic fluoropolymer according to claim 5, further comprising iodine or bromine in an amount ranging from 0.05% to 0.4% by weight.

7. The elastic fluoropolymer according to claim 6, wherein at least a portion of the iodine or bromine is bonded to the terminal carbon atoms of the elastic fluoropolymer.

8. The elastic fluoropolymer according to claim 5, wherein at least a portion of the iodine or bromine is provided by the elastic fluoropolymer further comprising monomer units of an iodine-containing or bromine-containing olefin.

9. The elastic fluoropolymer is the elastic fluoropolymer according to any one of claims 1 to 8, wherein the elastic fluoropolymer has a glass transition temperature of -30°C or lower.

10. The elastic fluoropolymer according to any one of claims 1 to 9, wherein, after curing, the elastic fluoropolymer has a 10% low-temperature elastic recovery (temperature retraction) at -30°C or below.

11. The elastic fluoropolymer according to any one of claims 1 to 10, wherein, after curing, the elastic fluoropolymer has a 70% low-temperature elastic recovery at -16°C or below.

12. The elastic fluoropolymer according to any one of claims 1 to 11, wherein, after curing, the elastic fluoropolymer has a difference in low-temperature elastic recovery below 14°C.

13. The elastic fluoropolymer according to any one of claims 1 to 12, wherein, after curing, the elastic fluoropolymer has a volume swelling degree of less than 28%.

14. The elastic fluoropolymer according to any one of claims 1 to 13, wherein, after curing, the elastic fluoropolymer has a compression set of less than 50%.

15. The elastic fluoropolymer according to any one of claims 1 to 14, wherein the elastic fluoropolymer has a Mooney viscosity in the range of 10 to 100.

16. A composition, An elastic fluoropolymer, comprising the following monomer units: 45 mol% to 65 mol% -CF2-CH2- and 8 mol% to 30 mol% -CF2-CF2- and 4.5 mol% to 25 mol% -CF2-CF(O-CF3)- and, 6 mol% to 20 mol% of -CF 2 -CF(O-CF 2 -CF 2 -O-(CF 2 -O) n -CF 3 )-(where n is 1 or 2), and an elastic fluoropolymer containing A composition comprising at least one additive.

17. The composition according to claim 16, wherein the at least one additive is selected from the group consisting of at least one filler, at least one processing aid, at least one coloring agent, and combinations thereof.

18. The composition according to claim 16, wherein the at least one additive comprises a peroxide curing agent.

19. The composition according to claim 18, wherein the peroxide curing agent is selected from the group consisting of organic peroxides and polyfunctional unsaturated cocrosslinking agents.

20. The composition according to any one of claims 16 to 19, wherein the elastic fluoropolymer further comprises an iodine-cured portion or a bromine-cured portion.

21. A composition, A first elastic fluoropolymer comprising the following monomer units: 45 mol% to 65 mol% -CF 2 -CH 2 -and, 8 mol% to 30 mol% -CF 2 -CF 2 -and, 4.5 mol% to 25 mol% -CF 2 -CF (O-CF) 3 )-and, 6 mol% to 20 mol% -CF 2 -CF (O-CF) 2 -CF 2 -O-(CF 2 -O) n -CF 3 A first elastic fluoropolymer comprising ) - [wherein n is 1 or 2], A composition comprising a second elastic fluoropolymer blended with the first elastic fluoropolymer.

22. The composition according to claim 21, wherein the first elastic fluoropolymer further comprises an iodine-cured moiety or a bromine-cured moiety.

23. The composition according to claim 21 or 22, wherein the second elastic fluoropolymer comprises a terpolymer of vinylidene fluoride, tetrafluoroethylene, and perfluoromethyl vinyl ether.

24. The composition according to any one of claims 21 to 23, wherein the first elastic fluoropolymer has a glass transition temperature of -30°C or lower.

25. The composition according to any one of claims 21 to 24, wherein the second elastic fluoropolymer has a glass transition temperature above -30°C.

26. The composition according to any one of claims 21 to 25, wherein the first elastic fluoropolymer and the second elastic fluoropolymer are combined in amounts selected to bring the composition to a predetermined glass transition temperature, the predetermined glass transition temperature being -30°C or lower.

27. The composition according to any one of claims 21 to 26, wherein the composition has a single predetermined glass transition temperature, and the predetermined glass transition temperature is -30°C or lower.

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