Polychlorotrifluoroethylene, and method for producing polychlorotrifluoroethylene

Abstract

Provided is a polychlorotrifluoroethylene containing chlorotrifluoroethylene units, wherein the content of the chlorotrifluoroethylene units is 95.0 to 100 mol% with respect to the total amount of all monomer units, and the ratio ((A) / (B)) of the area (A) of a peak derived from a double bond to the area (B) of a peak derived from a main skeleton is 0.020% or less.

Description

Polychlorotrifluoroethylene and method for producing polychlorotrifluoroethylene

[0001] The present disclosure relates to polychlorotrifluoroethylene and methods for producing polychlorotrifluoroethylene.

[0002] Patent Document 1 describes a method for improving the heat resistance of a chlorotrifluoroethylene polymer, which comprises treating the chlorotrifluoroethylene polymer with a fluorinating agent.

[0003] Japanese Patent Application Publication No. 5-170811

[0004] An object of the present disclosure is to provide polychlorotrifluoroethylene having excellent oxidation resistance.

[0005] According to the present disclosure, there is provided polychlorotrifluoroethylene containing chlorotrifluoroethylene units, in which the content of chlorotrifluoroethylene units is 95.0 to 100 mol % based on all monomer units, and the ratio ((A) / (B)) of the peak area (A) derived from double bonds to the peak area (B) derived from the main skeleton is 0.020% or less.

[0006] According to the present disclosure, polychlorotrifluoroethylene having excellent oxidation resistance can be provided.

[0007] Specific embodiments of the present disclosure will be described in detail below, but the present disclosure is not limited to the following embodiments.

[0008] Polychlorotrifluoroethylene (PCTFE) is known as a fluororesin having excellent chemical resistance and gas barrier properties. Patent Document 1 describes that the heat resistance of PCTFE is improved by treating PCTFE with a fluorinating agent. However, no method for improving the oxidation resistance of PCTFE has been investigated so far.

[0009] When PCTFE comes into contact with an oxidizing agent such as piranha solution, the durability of PCTFE against stress decreases. The inventors of the present invention have conducted research and found that the oxidation resistance of PCTFE is affected by the double bonds present in PCTFE, and that the oxidation resistance of PCTFE can be significantly improved by reducing the amount of double bonds present in PCTFE.

[0010] That is, the PCTFE of the present disclosure is a PCTFE that contains 95 to 100 mol% of chlorotrifluoroethylene (CTFE) units based on all monomer units, and in which the ratio ((A) / (B)) of the peak area (A) derived from double bonds to the peak area (B) derived from the main skeleton is 0.020% or less.

[0011] The configuration of the PCTFE of the present disclosure will be described in detail below.

[0012] (PCTFE) The PCTFE of the present disclosure is characterized in that the ratio ((A) / (B)) of the peak area (A) derived from double bonds to the peak area (B) derived from the main skeleton is 0.020% or less.

[0013] The ratio ((A) / (B)) of the peak area (A) derived from double bonds to the peak area (B) derived from the main skeleton indicates the proportion of double bonds present in the main chain of PCTFE. The lower the ratio ((A) / (B)), the smaller the amount of double bonds present in the main chain of PCTFE. The ratio ((A) / (B)) is, since this further improves the oxidation resistance of PCTFE, is preferably 0.015% or less, more preferably 0.012% or less.

[0014] CTFE is prepared, for example, by dechlorinating trifluorotrichloroethane, which contains CF as an impurity monomer. ２ = CHCl and CF ２ = CHF is inevitably produced. CTFE (CF ２When PCTFE is produced by polymerizing CTFE (CFCl), if these impurity monomers are incorporated into the main chain of PCTFE together with CTFE, dehydrofluorination or dehydrochlorination reactions readily proceed, resulting in the formation of double bonds in PCTFE. It has now been discovered that the presence of these double bonds is the cause of the decrease in the oxidation resistance of PCTFE.

[0015] The peak area (A) is the １９ It is the area of ​​the peak due to the double bond that appears in the F-NMR spectrum. When multiple peaks due to double bonds appear, the areas of all the peaks are summed up. The peak due to the double bond is usually １９ They appear in the chemical shift regions of −144 to −153 ppm and −176 to −188 ppm in the F-NMR spectrum.

[0016] The peak area (B) is the area of ​​PCTFE. １９ It is the area of ​​the peak derived from the main skeleton that appears in the F-NMR spectrum. When multiple peaks derived from the main skeleton appear, the areas of all the peaks are summed up. The main skeleton of PCTFE is the main chain skeleton composed of carbon chains. The peak derived from the main skeleton is usually １９ It appears in the chemical shift region of −75 to −144 ppm in the F-NMR spectrum.

[0017] The flow value of PCTFE is preferably 0.3 to 2.5 × 10 because the oxidation resistance of PCTFE is further improved. －３ cm ３ / sec, and more preferably 2.0 × 10 －３ cm ３ / sec or less, and more preferably 1.5 × 10 －３ cm ３ / sec or less, and even more preferably 1.0 × 10 －３ cm ３ / sec or less.

[0018] The flow value of PCTFE can be measured using a Koga type flow tester under the conditions of 230°C, a load of 980 N (100 kg), and a nozzle diameter of 1 mm. The flow value of PCTFE is the volume of PCTFE extruded from the nozzle per second.

[0019] The melting point of PCTFE is preferably 150° C. or higher, more preferably 190° C. or higher, and preferably 230° C. or lower, more preferably 217° C. or lower. The melting point is the temperature corresponding to the maximum value on the heat of fusion curve when the temperature is increased at a rate of 10° C. / min using a differential scanning calorimeter (DSC).

[0020] The PCTFE is not particularly limited as long as it contains CTFE units, and may be either a CTFE homopolymer or a polymer containing CTFE units and comonomer units (but excluding CTFE units).

[0021] The content of CTFE units in PCTFE is 95.0 to 100 mol % or more, preferably 98.0 mol % or more, more preferably 99.0 mol % or more, and even more preferably 99.9 mol % or more, based on all monomer units.

[0022] The comonomer constituting the comonomer unit that can be contained in PCTFE is not particularly limited as long as it is a monomer copolymerizable with CTFE, and examples thereof include ethylene, vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, fluoro(alkyl vinyl ether), (perfluorobutyl)ethylene, (perfluorohexyl)ethylene, perfluoro(1,1,2-trihydro-1-hexene), and perfluoro(1,1,5-trihydro-1-pentene). In one embodiment, the comonomer is CF ２ = CHCl and CF ２ = a monomer other than CHF.

[0023] The monomer composition of PCTFE is １９ It can be measured by F-NMR.

[0024] (Production Method of PCTFE) The PCTFE of the present disclosure is produced by a production method of PCTFE by polymerizing a monomer mixture containing CTFE, ２ = CHCl and CF ２It can be produced by using a monomer mixture having a ═CHF content of 250 ppm by mole or less based on the monomer mixture.

[0025] CF in the monomer mixture ２ = CHCl and CF ２ The content of =CHF is preferably 200 mol ppm or less, more preferably 160 mol ppm or less, and even more preferably 120 mol ppm or less, based on the monomer mixture, since the oxidation resistance of the resulting PCTFE is further improved. ２ = CHCl and CF ２ The lower limit of the =CHF content is not particularly limited, and may be, for example, 0.1 mol ppm or more, 10 mol ppm or more, or 20 mol ppm or more.

[0026] CF in the monomer mixture ２ = CHCl and CF ２ The content of =CHF can be measured by gas chromatography.

[0027] CF ２ = CHCl and CF ２ The monomer mixture having a content of =CHF within the above range may be, for example, CTFE, CF ２ = CHCl and CF ２ The crude composition containing CF = CHF was distilled, and the CF in the crude composition was ２ = CHCl and CF ２ = It can be prepared by reducing the content of CHF.

[0028] The crude composition can be distilled by a known method. For example, as described in Preparation Example 2 below, rectification can be performed using multiple rectification columns at a high heating amount and a high reflux ratio to remove CF4 in the crude composition. ２ = CHCl and CF ２ = The CHF content can be sufficiently reduced.

[0029] CTFE, CF ２ = CHCl and CF ２Crude compositions containing =CHF can be prepared by known methods, such as by dechlorinating trifluorotrichloroethane. Known methods for preparing CTFE typically involve the dechlorination of CF ２ = CHCl and CF ２ Therefore, when known methods for preparing CTFE are used, CTFE is usually prepared by adding CF to the CTFE. ２ = CHCl and CF ２ = Obtained as a crude composition containing CHF.

[0030] CF in crude composition ２ = CHCl and CF ２ The =CHF content is typically greater than 250 mole ppm, and may be 270 mole ppm or greater, or 300 mole ppm or greater.

[0031] The polymerization of the monomer mixture containing CTFE can be carried out by known polymerization method.Polymerization method is not particularly limited, and can be solution polymerization method, suspension polymerization method, emulsion polymerization method etc., but from the viewpoint of being able to smoothly produce PCTFE, suspension polymerization method is preferred.As suspension polymerization method, for example, the suspension polymerization method described in JP-B-47-44031 can be mentioned.

[0032] In one embodiment, polymerization can be carried out by charging the monomer mixture containing CTFE into a polymerization reactor, stirring the contents of the reactor, and maintaining the reactor at a predetermined polymerization temperature, then adding a polymerization initiator to start the polymerization reaction.Before starting the polymerization reaction, if necessary, solvent, additives, etc. can be charged into the reactor.After starting the polymerization reaction, solvent, monomer mixture, polymerization initiator, chain transfer agent, etc. can be added according to purpose.

[0033] The polymerization temperature of the monomer mixture containing CTFE is preferably 25°C or lower, more preferably 20°C or lower, and even more preferably 15°C or lower, since this further improves the oxidation resistance of the resulting PCTFE.

[0034] The polymerization time of the monomer mixture containing CTFE is usually 1 to 60 hours.

[0035] When PCTFE is produced by suspension polymerization, a slurry of PCTFE is usually obtained. The slurry is recovered from the reactor and, if desired, subjected to post-treatments such as washing and drying to obtain a powdery PCTFE product.

[0036] (Molding Material) The present disclosure also relates to a molding material containing the above-mentioned PCTFE.

[0037] The molding material of the present disclosure may be in the form of, for example, a powder, a granulated powder, granules, flakes, pellets, cubes, or beads.

[0038] The molding material of the present disclosure may have an extremely low metal content. In one embodiment, the content of Co, Cr, Cu, Fe, Mn, and Ni in the molding material of the present disclosure is 500 mass ppb or less, preferably 400 mass ppb or less, more preferably 300 mass ppb or less, even more preferably 250 mass ppb or less, even more preferably 220 mass ppb or less, particularly preferably 200 mass ppb or less, and may be 0.01 mass ppb or more or 0.1 mass ppb or more. By having the metal content in the molding material within the above range, for example, even when a molded body obtained from the molding material is used as a part used in the semiconductor manufacturing field, metal contamination of the semiconductor can be suppressed.

[0039] The molding material of the present disclosure contains PCTFE having a low ratio ((A) / (B)) of the peak area (A) derived from double bonds to the peak area (B) derived from the main skeleton, and therefore hydrogen fluoride and hydrogen chloride are unlikely to be generated from PCTFE. ２ = CHCl and CF ２ PCTFE obtained by polymerizing a monomer mixture with a low content of CHF is less likely to generate hydrogen fluoride or hydrogen chloride. Therefore, even when metal manufacturing equipment is used to manufacture PCTFE or prepare a molding material, the manufacturing equipment is less likely to corrode, and as a result, a molding material with an extremely low metal content can be obtained.

[0040] The metal content of the molding material is measured by weighing 1 g of the molding material, placing it in a platinum crucible (platinum purity 99.9%), and incinerating the sample with a gas burner or in an electric furnace at 500°C for 30 minutes, and then dissolving the ash remaining in the platinum crucible in 10% nitric acid to obtain a solution. The resulting solution can be measured using an ICP emission spectrometer (SPS3000, manufactured by Seiko Instruments Inc.) or a frameless atomic absorption spectrophotometer.

[0041] Furthermore, when the metal content in the molding material is extremely low (for example, when the metal content is less than 0.1 ppb by mass), the metal content may be measured by a method different from the above-mentioned measurement method. For example, it can be measured by the ashing method described in WO 94 / 28394. In the ashing method, the molding material is precisely weighed in the range of 2 to 6 mg and ashed by heating at 1100°C for 180 seconds in a graphite cuvette, and then analyzed using an atomic absorption spectrophotometer (polarized Zeeman atomic absorption spectrophotometer (Z-8100), manufactured by Hitachi, Ltd.).

[0042] The molding material of the present disclosure may contain various additives such as, for example, conductive materials, reinforcing agents, fillers, ultraviolet absorbers, heat stabilizers, and pigments.

[0043] (Molded Article) A molded article can be obtained by molding the above-mentioned PCTFE or the above-mentioned molding material.

[0044] The molding method is not particularly limited, and examples thereof include melt molding, and known methods such as extrusion molding, injection molding, transfer molding, inflation molding, compression molding, etc. These molding methods may be appropriately selected depending on the shape of the molded product to be obtained.

[0045] The molded article of the present disclosure can be suitably used in the fields of semiconductor manufacturing, chemical product manufacturing, electronic component manufacturing, etc. The molded article of the present disclosure can be used, for example, as sealing materials such as packings and gaskets; pump parts such as casings, impellers, valves, and plugs; chemical liquid tubes; and component materials used with cryogenic fluids, such as cryogenic butterfly valves.

[0046] The molded article of the present disclosure has excellent oxidation resistance and can therefore be suitably used, in particular, as a component that comes into contact with aqueous solutions of acids such as sulfuric acid, hydrochloric acid, nitric acid, and hydrofluoric acid, and chemical solutions such as hydrogen peroxide solution.

[0047] The molded article of the present disclosure has excellent oxidation resistance and can therefore be particularly suitably used as a component of semiconductor manufacturing equipment. Examples of such components include turntables for processing silicon wafers, peripheral components such as wafer guides, silicon wafer cleaning guides, chemical piping couplers, valves, and joints. Examples of turntables include those used in semiconductor cleaning equipment.

[0048] Although the embodiments have been described above, it will be understood that various changes in form and details can be made without departing from the spirit and scope of the claims.

[0049] <1> According to a first aspect of the present disclosure, there is provided polychlorotrifluoroethylene containing chlorotrifluoroethylene units, wherein the content of the chlorotrifluoroethylene units is 95.0 to 100 mol % based on all monomer units, and the ratio ((A) / (B)) of the peak area (A) derived from double bonds to the peak area (B) derived from the main skeleton is 0.020% or less. <2> According to a second aspect of the present disclosure, there is provided polychlorotrifluoroethylene having a flow value of 0.3 to 2.5 × 10 －３ cm ３ / sec. <3> According to a third aspect of the present disclosure, there is provided polychlorotrifluoroethylene according to the first or second aspect, in which the content of chlorotrifluoroethylene units is 99.9 to 100 mol % based on all monomer units. <4> According to a fourth aspect of the present disclosure, there is provided a molding material containing polychlorotrifluoroethylene according to any of the first to third aspects. <5> According to a fifth aspect of the present disclosure, there is provided a molding material according to the fourth aspect, in the form of a powder, a granulated product of a powder, a granule, a flake, a pellet, a cube, or a bead. <6> According to a sixth aspect of the present disclosure, there is provided a molding material according to the fourth or fifth aspect, in which the contents of Co, Cr, Cu, Fe, Mn, and Ni are 500 ppb by mass or less. <7> According to a seventh aspect of the present disclosure, there is provided a molded article obtained by molding the polychlorotrifluoroethylene according to the first or second aspect, or the molding material according to any one of the fourth to sixth aspects. <8> According to an eighth aspect of the present disclosure, there is provided a method for producing polychlorotrifluoroethylene by polymerizing a monomer mixture containing chlorotrifluoroethylene, wherein CF in the monomer mixture is ２ = CHCl and CF ２ <9> According to a ninth aspect of the present disclosure, there is provided a production method in which a content of CF₄CHF in the crude composition is 250 mol ppm or less relative to the monomer mixture. ２ = CHCl and CF ２ According to an eighth aspect of the present disclosure, there is provided a production method in which the monomer mixture is prepared by reducing the content of =CHF. <10> According to a tenth aspect of the present disclosure, there is provided the production method according to the eighth or ninth aspect, in which the polymerization temperature is 25°C or less.

[0050] Next, embodiments of the present disclosure will be described with reference to examples, but the present disclosure is not limited to these examples.

[0051] The values ​​in the examples were measured by the following methods.

[0052] <Amount of impurity monomer in monomer mixture> In this example, the impurity monomer is CF ２ = CHCl and CF ２ = CHF. The amount of impurity monomers in the monomer mixture relative to the amount of CTFE in the monomer mixture (CF ２ = CHCl and CF ２ The CTFE content (CHF content) was measured using a gas chromatograph GC8A (Shimadzu Corporation), a SUS column of 3 mmφ×10 m, and Octoil S packing under the following conditions: column temperature 45° C., detection temperature 80° C., CARRIER pressure 160 kPa, CARRIER gas He, and sample amount 1 cc. The CTFE content in the raw material monomer mixture was measured using a gas chromatograph GC8A (Shimadzu Corporation), a SUS column of 3 mmφ×10 m, and Octoil S packing under the following conditions: column temperature 45° C., detection temperature 80° C., CARRIER pressure 160 kPa, CARRIER gas He, and sample amount 1 cc. ２ = CHCl, CF ２ = Value obtained by subtracting the content of components other than CTFE, such as CHF, from 100 mol %.

[0053] <Flow Value of PCTFE> Using a Koga type flow tester CFT-500D (manufactured by Shimadzu Corporation), the volume of resin flowing per second (cm 3 ) was measured under the conditions of 230°C, a load of 980 N (100 kg), and a nozzle diameter of 1 mm. ３ / sec) was measured.

[0054] <Ratio of peak area ((A) / (B))> Melt １９ By F-NMR method, PCTFE １９ F-NMR spectrum was obtained. Measurement was performed using a nuclear magnetic resonance spectrometer AVANCE NEO 400 (manufactured by BRUKER) under conditions of 376.51 MHz, 240°C, and 500 accumulations. Peak area (A): Sum of peak areas appearing at -144 to -153 ppm and -176 to -188 ppm. Peak area (B): Sum of peak areas appearing at -75 to -144 ppm.

[0055] <Fatigue Test> (Preparation of Test Specimen) A 1.5 mmt sheet was prepared by melt compression molding PCTFE at 280° C. for 20 minutes, and the sheet was punched out with an ASTM D638 type IV dumbbell to prepare a test specimen.

[0056] (Immersion in Piranha Solution) The test pieces were arranged in a container, and hydrogen peroxide and sulfuric acid were poured into the container so that the ratio of 30% hydrogen peroxide to 98% sulfuric acid was 1:3. The test pieces were immersed in the solution for 24 hours. After immersion, the test pieces were washed with running water and wiped dry.

[0057] (Fatigue Test) Using a test piece immersed in piranha solution and a fatigue testing machine EHF-LV020k1 (manufactured by Shimadzu Corporation), a test was performed under the conditions of tensile mode, R = 0.1 (stress ratio R = minimum stress / maximum stress), maximum stress of 60% of the yield point of the tensile test, and 5 Hz, and the number of repetitions until the test piece broke was measured. Test pieces with a large number of repetitions to break have excellent oxidation resistance.

[0058] (Metal Content) The metal content of the pellet was measured by precisely weighing 1 g of the pellet, placing it in a platinum crucible (platinum purity 99.9%), and ashing the sample with a gas burner, or by ashing the sample in an electric furnace at 500°C for 30 minutes, and then dissolving the ash remaining in the platinum crucible in 10% nitric acid to obtain a solution. The contents of Co, Cr, Cu, Fe, Mn, and Ni were measured using the obtained solution and an ICP emission spectrometer (SPS3000, manufactured by Seiko Instruments Inc.).

[0059] Preparation Example 2 (Preparation of CTFE) A raw material monomer mixture having the following composition was used: CTFE content: 99.8 mol% CF ２ = CHF content: 300 mol ppm CF ２ = CHCl content: 700 mol ppm

[0060] A monomer mixture containing CTFE was prepared by rectifying the raw material monomer mixture. The raw material monomer mixture was supplied to the first rectification column at a rate of 175 kg / h. A fraction containing impurities was distilled from the top of the first rectification column at a rate of 1 kg / h, and a fraction containing CTFE was distilled from the bottom of the first rectification column at a rate of 174 kg / h. First rectification column Number of theoretical plates: 25 Heat amount: 2500 kcal / h Reflux ratio: 147 mole Pressure: 0.90 MPaG Top temperature: 38.1 ° C. Bottom temperature: 41.0 ° C.

[0061] Next, the fraction distilled from the bottom of the first fractionator was supplied to the second fractionator at a rate of 174 kg / h. From the bottom of the second fractionator, a fraction containing impurities was distilled at a rate of 1 kg / h, and from the top of the second fractionator, a fraction containing CTFE was distilled at a rate of 173 kg / h. Second fractionator Number of theoretical plates: 50 Heating amount: 60,000 kcal / h Reflux ratio: 9 mole Pressure: 0.45 MPaG Top temperature: 18.5 ° C. Bottom temperature: 28.4 ° C.

[0062] CF in the fraction (monomer mixture) distilled from the top of the second rectification column ２ = CHCl and CF ２ The total =CHF content was 80 mole ppm.

[0063] Preparation Example 8 (Preparation of CTFE) A monomer mixture containing CTFE was prepared in the same manner as in Preparation Example 2, except that the heating rate of the second fractionator was changed to 20,000 kcal / h and the reflux ratio was changed to 2 moles. ２ = CHCl and CF ２ The total =CHF content was 354 mole ppm.

[0064] Preparation Examples 1, 3 to 7 (Preparation of CTFE) The monomer mixtures obtained in Preparation Examples 2 and 8 were mixed in arbitrary proportions to prepare monomer mixtures having the amounts of impurity monomers shown in Table 1.

[0065] Example 1 (Production of PCTFE) PCTFE was produced using the suspension polymerization method described in Japanese Patent Publication No. 47-44031. The monomer mixture obtained in Preparation Example 1 was polymerized at a polymerization temperature of 12°C for 42 hours to obtain powdery PCTFE. The results are shown in Table 1.

[0066] Examples 2 to 6 and Comparative Examples 1 and 2 Powdery PCTFE was obtained in the same manner as in Example 1, except that the monomer mixture obtained in Preparation Examples 2 to 8 was used instead of the monomer mixture obtained in Preparation Example 1, and the monomer mixture was polymerized at the polymerization temperature and polymerization time shown in Table 1. The results are shown in Table 1. Furthermore, the powdery PCTFE was molded using an extruder at 310°C to prepare pellets, and the metal contents (Co, Cr, Cu, Fe, Mn, and Ni contents) in the pellets were measured. The results are shown in Table 2.

[0067]

[0068]

Claims

1. Polychlorotrifluoroethylene containing chlorotrifluoroethylene units, The chlorotrifluoroethylene unit content is 95.0 to 100 mol% relative to the total monomer units. The ratio of the peak area (A) derived from the double bond to the peak area (B) derived from the main skeleton ((A) / (B)) is 0.020% or less. Polychlorotrifluoroethylene.

2. The flow value is 0.3 to 2.5 × 10 －３ cm ３ Polychlorotrifluoroethylene according to claim 1, wherein the value is / sec.

3. The polychlorotrifluoroethylene according to claim 1, wherein the content of chlorotrifluoroethylene units is 99.9 to 100 mol% of the total monomer units.

4. A molding material containing polychlorotrifluoroethylene as described in claim 1.

5. The molding material according to claim 4, which is a powder, a granulated product of a powder, granules, flakes, pellets, cubes, or beads.

6. The molding material according to claim 4, wherein the content of Co, Cr, Cu, Fe, Mn, and Ni is 500 ppb by mass or less.

7. A molded article obtained by molding the polychlorotrifluoroethylene described in claim 1, or the molding material described in claim 4.

8. A method for producing polychlorotrifluoroethylene, which involves polymerizing a monomer mixture containing chlorotrifluoroethylene, CF in the monomer mixture ２ = CHCl and CF ２ = The CHF content is 250 mol ppm or less relative to the monomer mixture. Manufacturing method.

9. By distilling a crude composition containing chlorotrifluoroethylene, the CF in the crude composition is obtained. ２ = CHCl and CF ２ = The manufacturing method according to claim 8, wherein the CHF content is reduced to prepare the monomer mixture.

10. The manufacturing method according to claim 8 or 9, wherein the polymerization temperature is 25°C or lower.