Preparation method and device of perfluorinated sulfonic acid resin dispersion liquid with low metal ion content

Abstract

The invention discloses a preparation method and device of perfluorinated sulfonic acid resin dispersion liquid with low metal ion content. The method comprises the following steps: 1) carrying out acid pickling and water washing pretreatment on perfluorinated sulfonic acid resin; 2) mixing the pretreated perfluorosulfonic acid resin and a first solvent under heating and pressure control conditions, and dispersing the resin; and 3) after the resin dispersion is completed, cooling the feed liquid to a certain temperature, adding a second solvent, mixing, filtering and concentrating to obtain the perfluorosulfonic acid resin dispersion liquid. The perfluorosulfonic acid resin is subjected to acid pickling and water washing purification treatment, and residual metal ions in the resin can be greatly reduced. According to the invention, the contact between the perfluorosulfonic acid resin and the metal material is avoided in the whole process flow of resin dispersion, second solvent supplementation, filtration and concentration, so that the metal ion pollution caused by corrosion is avoided, and the metal ion content of the dispersion liquid can be controlled at a lower level.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer materials, and particularly relates to a preparation method and device for a perfluorosulfonic acid resin dispersion liquid with low metal ion content. Background Art

[0002] As an efficient and environmentally friendly power generation device, the proton exchange membrane fuel cell (PEMFC) has attracted more and more attention. Since it does not go through a heat engine process, the hydrogen fuel cell is not restricted by the Carnot cycle and has advantages such as high specific power, high energy efficiency, low operating temperature, and fast startup speed, and is particularly suitable for use as a power battery. Whether the hydrogen fuel cell can be commercially promoted on a large scale, in addition to cost factors, whether it has excellent performance and a long service life are two key technical indicators.

[0003] The performance degradation of the hydrogen fuel cell is usually due to the aging and degradation of the key material, the proton exchange membrane (PEM), which causes a decline in function and further affects the performance and service life of the entire battery pack. The proton exchange membrane of the hydrogen fuel cell is usually prepared from perfluorosulfonic acid resin, such as the Nafion series resin of DuPont, and its molecular structure includes a polytetrafluoroethylene main chain and a side chain containing -SO 3 H, as shown below:

[0004]

[0005] In addition to being affected by the chemical structure of the perfluorosulfonic acid resin and the membrane preparation process, metal ion contamination will also affect the performance and life of the proton exchange membrane. One is that metal ions replace the protons of -SO 3 H, reducing the ion exchange equivalent weight (EW) of the membrane and lowering the proton conductivity of the membrane. The other is that it promotes the degradation of the membrane and shortens its life.

[0006] The conductivity of the proton exchange membrane depends on its ion exchange equivalent weight and water content. Metal ions can replace the protons of -SO 3 H to form sulfonates, producing the "cation effect of the proton exchange membrane", reducing the ion exchange equivalent weight of the membrane, and at the same time reducing the number of water molecules bound to -SO 3 H, thereby reducing the proton conductivity of the membrane. The binding ability of most metal ions to sulfonate groups is stronger than that of protons, so there is a certain degree of "cation effect".

[0007] During the reaction of oxygen and protons in the hydrogen fuel cell, in addition to generating H 2 O, some H 2 O 2 . Fe2+ , Cr 3+ , Ni 2+ , Cu 2+ and other metal ions catalyze the decomposition of H 2 O 2 to generate HO· and HOO· free radicals, and the HO· and HOO· free radicals will attack the side chains of perfluorosulfonic acid resin to promote its degradation, thereby reducing the lifespan of the proton exchange membrane. Among them, the effects of Fe 2+ and Cu 2+ are the most significant.

[0008] When preparing the proton exchange membrane by the solution casting method, the perfluorosulfonic acid resin needs to be dispersed in a solvent under certain temperature and pressure, and then the resin dispersion is cast onto a mold and the solvent is removed to form a film. The perfluorosulfonic acid resin contains a large amount of -SO 3 H, the dispersion solvent is usually alcohol and water, and the dispersion is strongly acidic. The preparation of the perfluorosulfonic acid resin dispersion requires relatively high temperature and pressure. For example, the temperature usually needs to be higher than 200 °C, and the pressure usually needs to be higher than 1.0 MPa. For the reaction kettle used in the preparation of perfluorosulfonic acid resin, if non-metallic materials such as quartz glass are selected, it is difficult to withstand the high pressure required for resin dispersion. If metal materials are selected, even Hastelloy with strong corrosion resistance to sulfonic acid, corrosion cannot be avoided. The existing methods for preparing perfluorosulfonic acid resin dispersion usually use a high-pressure reaction kettle made of metal materials, so metal ion contamination cannot be avoided, especially Fe 2+ , Cr 3+ , Ni 2+ , Cu 2+ and other metal ions. SUMMARY OF THE INVENTION

[0009] In order to improve the deficiencies of the prior art, the present invention provides a method and device for preparing a perfluorosulfonic acid resin dispersion, and the method and device can control the metal ion content of the dispersion at a low level.

[0010] The technical solution adopted by the present invention is as follows:

[0011] A method for preparing a perfluorosulfonic acid resin dispersion, the preparation method comprising the following steps:

[0012] 1) Pretreat the perfluorosulfonic acid resin, including pickling and washing;

[0013] 2) Mix the pretreated perfluorosulfonic acid resin and the first solvent under heating and pressure control conditions for resin dispersion;

[0014] 3) After the resin dispersion is completed, lower the temperature of the feed liquid to a certain temperature, add the second solvent, mix, filter, and concentrate to obtain the perfluorosulfonic acid resin dispersion;

[0015] In step 2), the first solvent is a mixed solvent of an alcohol compound and water;

[0016] In step 3), the second solvent is an alcohol compound.

[0017] According to the present invention, in step 1), the pickling is soaking and washing with an acid such as sulfuric acid, hydrochloric acid, nitric acid, etc., and preferably soaking and washing with sulfuric acid.

[0018] According to the present invention, in step 1), the water washing is soaking and washing with water.

[0019] According to the present invention, in step 1), the above pickling and water washing can be carried out one or more times repeatedly according to the metal ion content level in the perfluorosulfonic acid resin.

[0020] According to the present invention, in step 1), the pickling and water washing are carried out in a non-metallic material or a stirring kettle with a non-metallic material lining layer (such as a glass kettle, an enamel kettle, etc.). For example, the stirring kettle is also provided with a stirring paddle made of a non-metallic material; specifically, the non-metallic material is, for example, polytetrafluoroethylene.

[0021] According to the present invention, in step 1), after the pickling is completed, the resin needs to be filtered and separated, and the filtering operation is completed by a filter made of a non-metallic material or a filter with a non-metallic material lining layer.

[0022] According to the present invention, in step 1), after the water washing is completed, the resin needs to be filtered and separated, and the filtering operation is completed by a filter made of a non-metallic material or a filter with a non-metallic material lining layer.

[0023] According to the present invention, step 2) is carried out in a reaction kettle, and the inner wall of the reaction kettle is provided with a high-temperature resistant non-metallic material lining layer.

[0024] According to the present invention, the kettle body of the reaction kettle is made of stainless steel.

[0025] According to the present invention, a thermometer is provided inside the reaction kettle, and a thermometer thermocouple sleeve is provided outside the thermometer; a bottom pipe is provided inside the reaction kettle; a stirring paddle is provided at the upper part of the reaction kettle; the thermometer thermocouple sleeve, the bottom pipe and the stirring paddle are all made of high-temperature resistant non-metallic materials.

[0026] In the present invention, the high-temperature resistant non-metallic material is, for example, silicon carbide material, quartz glass, high-temperature resistant ceramic, etc.

[0027] According to the present invention, a reaction kettle jacket is provided outside the reaction kettle.

[0028] According to the present invention, a heat preservation layer is provided outside the reaction kettle jacket.

[0029] According to the present invention, the reactor is connected to subsequent equipment (such as a stirring kettle) through a pipeline, and the pipeline is made of a non-metallic material such as polytetrafluoroethylene or has a non-metallic material lining layer.

[0030] According to the present invention, in step 2), the alcohol compound in the first solvent is selected from saturated monohydric alcohols that are miscible with water. For example, the alcohol compound is selected from at least one of methanol, ethanol, n-propanol, and isopropanol.

[0031] According to the present invention, in step 2), the mass ratio of the alcohol compound to water in the first solvent is 0.2:1 - 2.0:1, preferably 0.5:1 - 1.5:1.

[0032] According to the present invention, in step 2), the heating temperature is not lower than 200°C, preferably 200°C - 250°C.

[0033] According to the present invention, in step 2), the pressure of the reaction system is 1.0 MPa(g) - 8.0 MPa(g). The pressure is controlled by a pressure control valve. When the pressure in the kettle is higher than a certain value, the pressure control valve opens to discharge some gas. When the pressure in the kettle is lower than a certain value, the pressure control valve opens to supplement some nitrogen.

[0034] According to the present invention, in step 2), the mixing time is not less than 1.0 hour, preferably 2.5 hours - 3.5 hours, and more preferably 3 hours.

[0035] According to the present invention, in step 3), the alcohol compound in the second solvent is selected from saturated monohydric alcohols that are miscible with water, such as at least one of methanol, ethanol, n-propanol, or isopropanol.

[0036] According to the present invention, in step 3), the addition amount of the second solvent is more than 100 wt% of the water feed amount in the first solvent, for example, more than 150 wt%.

[0037] According to the present invention, in step 3), the addition of the second solvent and mixing are carried out in a stirring kettle made of a non-metallic material such as a glass kettle or an enamel kettle or having a non-metallic material lining layer.

[0038] According to the present invention, in step 3), the filtration operation is carried out on a filter made of a non-metallic material such as polytetrafluoroethylene or having a non-metallic material lining layer.

[0039] According to the present invention, in step 3), the mixing temperature is 60°C - 80°C, and the mixing time is not less than 20 min, preferably 20 min - 30 min.

[0040] According to the present invention, in step 3), the concentration is carried out in a rectification column, and the concentration is carried out under reduced pressure, and the concentration temperature is not higher than 60 °C. Exemplarily, the operating parameters of the rectification column are as follows:

[0041] The number of theoretical plates is 10 - 26, for example 20, the pressure is 5 KPa(a) - 8 KPa(a), the vaporization temperature at the bottom of the column is 26 °C - 34 °C, the condensation temperature at the top of the column is 0 °C - 10 °C, and the reflux distribution ratio is 3 - 5.

[0042] In the present invention, the rectification column is used for the concentration under reduced pressure of the dispersion liquid.

[0043] According to the present invention, the rectification column in step 3) is connected to the reaction kettle; or the rectification column is connected to the stirring kettle for replenishing the second solvent; specifically, the material of the rectification column is a non-metallic material such as glass or a non-metallic material lined layer.

[0044] According to the present invention, in step 3), in the perfluorosulfonic acid resin dispersion liquid, the content of the perfluorosulfonic acid resin is 20 wt% - 24 wt%, preferably 22 wt%.

[0045] The present invention also provides a device for implementing the preparation method of the above perfluorosulfonic acid resin dispersion liquid. The device includes at least one group of stirring kettles, a reaction kettle, a stirring kettle, and a rectification column.

[0046] Among them, the at least one group of stirring kettles is used for the pretreatment of the perfluorosulfonic acid resin.

[0047] The reaction kettle is used for mixing the perfluorosulfonic acid resin and the first solvent under heating and pressure control conditions for resin dispersion.

[0048] The stirring kettle located behind the reaction kettle is used for replenishing the second solvent.

[0049] The rectification column is used for concentration.

[0050] Specifically, the reaction kettle is connected to the rectification column; or the stirring kettle for replenishing the second solvent is connected to the rectification column; the material of the rectification column is a non-metallic material (such as glass) or a non-metallic material lined layer.

[0051] According to the present invention, the at least one group of stirring kettles is used for the pretreatment of the perfluorosulfonic acid resin, and the stirring paddle in the stirring kettle is made of a non-metallic material such as polytetrafluoroethylene.

[0052] According to the present invention, the at least one set of stirring kettles includes two sets of stirring kettles. The previous set includes several stirring kettles for pickling; the latter set includes several stirring kettles for water washing. A filter is arranged between the pickling stirring kettles and the water washing stirring kettles; and / or, a filter is arranged between the water washing stirring kettles and the reaction kettle. Specifically, the filter adopts a non-metallic material such as polytetrafluoroethylene or a filter with a non-metallic material lining layer.

[0053] According to the present invention, the inner wall of the reaction kettle is provided with a layer of high-temperature resistant non-metallic material lining layer.

[0054] According to the present invention, the kettle body of the reaction kettle is made of stainless steel.

[0055] According to the present invention, the top of the reaction kettle is further provided with a stainless steel kettle cover.

[0056] According to the present invention, a thermometer is arranged inside the reaction kettle, and a thermometer thermocouple sleeve is arranged outside the thermometer; a bottom pipe is arranged inside the reaction kettle; a stirring paddle is arranged at the upper part of the reaction kettle; the thermometer thermocouple sleeve, the bottom pipe and the stirring paddle are all made of high-temperature resistant non-metallic materials.

[0057] According to the present invention, a reaction kettle jacket is arranged outside the reaction kettle.

[0058] According to the present invention, a heat preservation layer is arranged outside the reaction kettle jacket.

[0059] According to the present invention, the upper part of the reaction kettle is connected to a nitrogen pipeline, and at least one pressure control valve and at least one pressure gauge are arranged on the nitrogen pipeline.

[0060] According to the present invention, a stirring kettle is arranged after the reaction kettle for adding a second solvent in a supplementary manner, and the stirring paddle in the stirring kettle adopts a non-metallic material such as polytetrafluoroethylene.

[0061] According to the present invention, a rectification column is arranged after the stirring kettle for adding the second solvent in a supplementary manner for rectification and concentration, and the rectification column adopts a non-metallic material such as glass or a rectification column with a non-metallic material lining layer.

[0062] According to the present invention, the reaction kettle is connected to the stirring kettle for adding the second solvent in a supplementary manner through a pipeline, and the stirring kettle for adding the second solvent in a supplementary manner is connected to the rectification column through a pipeline and a filter, and the pipeline and the filter both adopt a non-metallic material such as polytetrafluoroethylene or a pipeline and a filter with a non-metallic material lining layer.

[0063] The beneficial effects of the present invention:

[0064] The present invention provides a preparation method and device for a perfluorosulfonic acid resin dispersion with low metal ion content. The method and device have the following advantages: (1) By subjecting the perfluorosulfonic acid resin to pickling and water washing purification treatments, the residual metal ions in the resin can be greatly reduced; (2) The reaction kettle is selected with a stainless steel kettle body and a high-temperature resistant non-metallic material lining, and accessories such as the stirring paddle, bottom insertion pipe, and thermometer thermocouple sleeve in the kettle are made of high-temperature resistant non-metallic materials, meeting the high-temperature and high-pressure conditions required for resin dispersion while avoiding contact between the resin and metal materials; (3) All processes such as resin purification, dispersion, filtration, solvent supplementation, and vacuum concentration avoid contact between the perfluorosulfonic acid resin and metal materials, avoiding metal ion contamination during the preparation process of the dispersion; (4) Through the control strategy of avoiding introduction during resin purification and preparation processes, the metal ion content of the dispersion can be controlled at a low level. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 It is a process flow schematic diagram of the preparation method of the perfluorosulfonic acid resin dispersion of the present invention.

[0066] Figure 2 It is a schematic diagram of the reaction kettle for preparing the perfluorosulfonic acid resin dispersion of the present invention.

[0067] Among them, Figure 2 The reference numerals in are: 1, heat insulation layer; 2, reaction kettle jacket; 3, stainless steel kettle body; 4, silicon carbide material lining layer; 5, silicon carbide material stirring paddle; 6, silicon carbide material sleeve of thermometer thermocouple; 7, silicon carbide material bottom insertion pipe; 8, stainless steel kettle cover; 9, fastening bolt; 10, pressure control valve; 11, pressure control valve; 12, pressure gauge; 13, pressure gauge. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0068] The technical solution of the present invention will be further described in detail below in combination with specific embodiments. It should be understood that the following embodiments are only for illustrative explanation of the present invention and should not be construed as limiting the protection scope of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0069] Unless otherwise specified, the raw materials and reagents used in the following embodiments are all commercially available products or can be prepared by known methods.

[0070] The preparation device for the perfluorosulfonic acid resin dispersion of the present invention is as follows:

[0071] As Figure 1 and Figure 2 shown, the device includes a stirring kettle, reaction kettle 1, stirring kettle, and rectifying column arranged in sequence, and a layer of silicon carbide material lining layer 4 is provided on the inner wall of the reaction kettle.

[0072] Among them, the stirring tank before the reactor is used for pickling and water washing of perfluorosulfonic acid resin. The stirring tank after the reactor is used for supplementing the second solvent.

[0073] Among them, there are two stirring tanks before the reactor. The previous stirring tank is used for pickling, and the latter stirring tank is used for water washing.

[0074] Among them, the reactor is used for mixing perfluorosulfonic acid resin and the first solvent under heating and pressurization conditions to carry out resin dispersion.

[0075] The reactor body is made of stainless steel, that is, the stainless steel reactor body 3. The top of the reactor is also provided with a stainless steel reactor cover 8.

[0076] A thermometer is provided inside the reactor, and a thermometer thermocouple sleeve 6 is provided outside the thermometer; a stirring paddle 5 made of high-temperature resistant non-metallic materials such as silicon carbide is provided at the upper part of the reactor; both the thermometer thermocouple sleeve and the stirring paddle are made of high-temperature resistant non-metallic materials such as silicon carbide.

[0077] The outer layer of the reactor is provided with a reactor jacket 2.

[0078] The outer layer of the reactor jacket is provided with a heat insulation layer 1.

[0079] The reactor can also be connected to the stirring tank through a pipeline. The pipeline is made of non-metallic materials such as polytetrafluoroethylene or has a non-metallic material inner lining layer. Inside the reactor, the pipeline is inserted into the bottom of the reactor, that is, a high-temperature resistant non-metallic material bottom pipe 7 made of silicon carbide.

[0080] The upper part of the reactor is connected to a nitrogen pipeline. There are 2 pressure control valves 10 and 11 and 2 pressure gauges 12 and 13 on the nitrogen pipeline.

[0081] The rectifying column is made of non-metallic materials such as glass or has a non-metallic material inner lining layer.

[0082] Exemplarily, the following examples and comparative examples use EW1050 type perfluorosulfonic acid resin with an ion exchange equivalent of 1050 g / mol and EW850 type resin with an ion exchange equivalent of 850 g / mol as raw materials to prepare the dispersion liquid. The method and device of the present invention can be used for but not limited to the preparation of dispersion liquids of the above two types of perfluorosulfonic acid resins.

[0083] Figure 1 It is a process flow schematic diagram of the method for preparing the perfluorosulfonic acid resin dispersion liquid of the present invention.

[0084] Such as Figure 1As shown in the figure, the perfluorosulfonic acid resin is pickled in a stirring kettle, and then filtered through a filter made of non-metallic materials such as polytetrafluoroethylene or a filter with a non-metallic material lining layer. The filtered resin is transferred to a stirring kettle for washing with water, and then filtered through a filter made of non-metallic materials such as polytetrafluoroethylene or a filter with a non-metallic material lining layer. The filtered resin and the first solvent are added to a high-pressure reaction kettle to control the temperature and pressure for dispersion. The obtained liquid material after resin dispersion is transferred to a stirring kettle, the second solvent is added, and then it is transferred to a glass rectification tower or a rectification tower with a non-metallic material lining layer for vacuum concentration. Part of the solvent is taken out from the top of the tower, and a dispersion liquid is obtained at the bottom of the tower.

[0085] Example 1

[0086] (1) Add 1.5 kg of EW1050 perfluorosulfonic acid resin and 9.0 kg of sulfuric acid with a concentration of 20 wt% to a stirring kettle, stir at room temperature for 24 hours, and filter. Add the resin obtained by filtration after sulfuric acid washing and 9.0 kg of ultrapure water to a glass kettle, stir at room temperature for 24 hours, and filter to obtain the purified perfluorosulfonic acid resin.

[0087] (2) Add the purified perfluorosulfonic acid resin, 6.75 kg of ethanol, and 6.75 kg of ultrapure water to the high-pressure reaction kettle described in the present invention. Set the pressure threshold value after the nitrogen supplementary pressure control valve to 5.9 MPa(g), and set the pressure threshold value before the gas release pressure control valve to 6.1 MPa(g). Raise the temperature in the high-pressure reaction kettle to 250 °C, control the temperature and stir for 3 hours. Transfer the liquid material in the high-pressure reaction kettle to a stirring kettle, add 12.5 kg of n-propanol, and stir for 30 minutes. Transfer the liquid material after adding n-propanol to a glass rectification tower for vacuum concentration. Part of the solvent is taken out from the top of the tower, and a resin dispersion liquid with a content of 22.0 wt% is obtained at the bottom of the tower. Among them, in the dispersion liquid, the resin content is 22.0 wt%, the n-propanol content is 43.1 wt%, the ethanol content is 1.0 wt%, and the water content is 33.9 wt%.

[0088] The detection results of the metal ion contents of the EW1050 perfluorosulfonic acid resin, the purified resin, and the resin dispersion liquid are shown in Table 1.

[0089] Table 1 Detection results of the metal ion contents of the samples in Example 1

[0090]

[0091] Example 2

[0092] (1) Add 1.5 kg of EW850 perfluorosulfonic acid resin and 9.0 kg of sulfuric acid with a concentration of 20 wt% to a glass kettle, stir at room temperature for 24 hours, and filter. Add the resin obtained by filtration after sulfuric acid washing and 9.0 kg of ultrapure water to a glass kettle, stir at room temperature for 24 hours, and filter to obtain the purified perfluorosulfonic acid resin.

[0093] (2) Add the purified perfluorosulfonic acid resin, 6.75 kg of ethanol, and 6.75 kg of ultrapure water into the high-pressure reactor described in the present invention. Set the pressure threshold after the nitrogen make-up pressure control valve to 5.9 MPa(g), and set the pressure threshold before the gas relief pressure control valve to 6.1 MPa(g). Raise the temperature inside the high-pressure reactor to 250 °C and stir while controlling the temperature for 3 hours. Transfer the liquid in the high-pressure reactor to a stirring kettle, add 12.5 kg of n-propanol, and stir for 30 minutes. Transfer the liquid after adding n-propanol to a glass distillation column for concentration under reduced pressure. Part of the solvent is taken out from the top of the column, and a resin dispersion with a content of 22.0 wt% is obtained at the bottom of the column. Among them, in the dispersion, the resin content is 22.0 wt%, the n-propanol content is 43.1 wt%, the ethanol content is 1.0 wt%, and the water content is 33.9 wt%.

[0094] The detection results of the metal ion contents of the EW850 perfluorosulfonic acid resin, the purified resin, and the resin dispersion are shown in Table 2.

[0095] Table 2 Detection results of the metal ion contents of the samples in Example 2

[0096]

[0097] Comparative Example 1

[0098] The difference between Comparative Example 1 and Example 1 is that step (1) is not included, and 1.5 kg of unpurified EW1050 perfluorosulfonic acid resin is used to replace the purified perfluorosulfonic acid resin in step (2). A resin dispersion with a content of 22.0 wt% is obtained at the bottom of the column. Among them, in the dispersion, the resin content is 22.0 wt%, the n-propanol content is 43.1 wt%, the ethanol content is 1.0 wt%, and the water content is 33.9 wt%.

[0099] The detection results of the metal ion contents of the EW1050 perfluorosulfonic acid resin dispersion prepared by the above method and device are shown in Table 3.

[0100] Table 3 Detection results of the metal ion contents of the dispersion obtained in Comparative Example 1

[0101]

[0102] Comparative Example 2

[0103] The difference between Comparative Example 2 and Example 2 is that step (1) is not included, and 1.5 kg of unpurified EW850 perfluorosulfonic acid resin is used to replace the purified perfluorosulfonic acid resin in step (2). A resin dispersion with a content of 22.0 wt% is obtained at the bottom of the column. Among them, in the dispersion, the resin content is 22.0 wt%, the n-propanol content is 43.1 wt%, the ethanol content is 1.0 wt%, and the water content is 33.9 wt%.

[0104] The detection results of the metal ion content of the EW850 perfluorosulfonic acid resin dispersion prepared by the above method and device are shown in Table 4.

[0105] Table 4 Detection results of the metal ion content of the dispersion obtained in Comparative Example 2

[0106]

[0107] It can be seen from Comparative Examples 1-2 that the perfluorosulfonic acid resin was not purified by pickling and water washing. Due to the relatively high metal ion content of the resin, the metal ion content of the prepared dispersion was significantly higher than that of Examples 1-2, especially the contents of K, Fe, and Cu ions were significantly higher.

[0108] Comparative Example 3

[0109] 1.5 kg of EW1050 perfluorosulfonic acid resin was purified by pickling and water washing, and then 6.75 kg of ethanol and 6.75 kg of ultrapure water were added to a high-pressure reactor with the material of the reactor body, the stirring paddle in the reactor, the bottom pipe, and the thermometer thermocouple sleeve being Hastelloy C-276 alloy. The pressure threshold value of the valve behind the nitrogen supplement pressure control valve was set to 5.9 MPa(g), and the pressure threshold value in front of the gas release pressure control valve was set to 6.1 MPa(g). The temperature in the high-pressure reactor was raised to 250 °C and stirred at a controlled temperature for 3 hours. The liquid in the high-pressure reactor was transferred to a stirring kettle, and 12.5 kg of n-propanol was added and stirred for 30 minutes. The liquid after adding n-propanol was transferred to a glass rectification column for vacuum concentration, and part of the solvent was taken out from the top of the column, and a resin dispersion with a content of 22.0 wt% was obtained at the bottom of the column. Among them, in the dispersion, the resin content was 22.0 wt%, the n-propanol content was 43.1 wt%, the ethanol content was 1.0 wt%, and the water content was 33.9 wt%.

[0110] The detection results of the metal ion content of the EW1050 perfluorosulfonic acid resin dispersion prepared by the above method and device are shown in Table 5.

[0111] Table 5 Detection results of the metal ion content of the dispersion obtained in Comparative Example 3

[0112]

[0113] Comparative Example 4

[0114] 1.5 kg of EW850 perfluorosulfonic acid resin was purified by pickling and washing with water, and then 6.75 kg of ethanol and 6.75 kg of ultrapure water were added together into a high-pressure reactor. The materials of the reactor body, the stirring paddle inside the reactor, the bottom pipe, the thermometer thermocouple sleeve and other accessories were all Hastelloy C-276 alloy. The pressure threshold value after the nitrogen replenishing pressure control valve was set to 5.9 MPa(g), and the pressure threshold value before the gas release pressure control valve was set to 6.1 MPa(g). The temperature inside the high-pressure reactor was raised to 250 °C and stirred for 3 hours while controlling the temperature. The liquid material inside the high-pressure reactor was transferred into a stirring kettle, and 12.5 kg of n-propanol was added and stirred for 30 minutes. The liquid material after adding n-propanol was transferred into a glass distillation column for vacuum concentration. Part of the solvent was taken out from the top of the column, and a resin dispersion with a content of 22.0 wt% was obtained at the bottom of the column. Among them, in the dispersion, the resin content was 22.0 wt%, the n-propanol content was 43.1 wt%, the ethanol content was 1.0 wt%, and the water content was 33.9 wt%.

[0115] The detection results of the metal ion content of the EW850 perfluorosulfonic acid resin dispersion prepared by the above method and device are shown in Table 6.

[0116] Table 6 Detection results of the metal ion content of the dispersion obtained in Comparative Example 4

[0117]

[0118] It can be seen from Comparative Examples 3-4 that the resin dispersion was completed in a high-pressure reactor with the reactor body and the internal accessories made of Hastelloy C-276 alloy. Due to metal ion pollution caused by equipment corrosion, the metal ion content of the prepared dispersion was significantly higher than that of Examples 1-2, especially the contents of Ni, Cr, and Fe ions were significantly higher.

[0119] Comparative Example 5

[0120] 1.5 kg of EW1050 perfluorosulfonic acid resin was purified by pickling and washing with water, and then 6.75 kg of ethanol and 6.75 kg of ultrapure water were added together to a high-pressure reactor. The materials of the reactor body, the stirring paddle inside the reactor, the bottom pipe, the thermocouple sleeve of the thermometer, etc. are all Hastelloy C-276 alloy. There is a quartz glass layer on the inner wall of the reactor body, but there is a quartz glass sleeve placed inside the reactor. The pressure threshold value after the nitrogen make-up pressure control valve is set to 5.9 MPa(g), and the pressure threshold value before the gas relief pressure control valve is set to 6.1 MPa(g). The temperature inside the high-pressure reactor was raised to 250 °C and stirred under temperature control for 3 hours. The liquid in the high-pressure reactor was transferred to a stirring kettle, and 12.5 kg of n-propanol was added and stirred for 30 minutes. The liquid after adding n-propanol was transferred to a glass rectification column for vacuum concentration. Part of the solvent was taken out from the top of the column, and a resin dispersion with a content of 22.0 wt% was obtained at the bottom of the column. Among them, in the dispersion, the resin content is 22.0 wt%, the n-propanol content is 43.1 wt%, the ethanol content is 1.0 wt%, and the water content is 33.9 wt%.

[0121] The detection results of the metal ion content of the EW1050 perfluorosulfonic acid resin dispersion prepared by the above method and device are shown in Table 7.

[0122] Table 7 Detection results of the metal ion content of the dispersion obtained in Comparative Example 5

[0123]

[0124] Comparative Example 6

[0125] 1.5 kg of EW850 perfluorosulfonic acid resin was purified by pickling and washing with water, and then 6.75 kg of ethanol and 6.75 kg of ultrapure water were added together to a high-pressure reactor. The materials of the reactor body, the stirring paddle inside the reactor, the bottom pipe, the thermocouple sleeve of the thermometer, etc. are all Hastelloy C-276 alloy. There is a quartz glass layer on the inner wall of the reactor body, but there is a quartz glass sleeve placed inside the reactor. The pressure threshold value after the nitrogen make-up pressure control valve is set to 5.9 MPa(g), and the pressure threshold value before the gas relief pressure control valve is set to 6.1 MPa(g). The temperature inside the high-pressure reactor was raised to 250 °C and stirred under temperature control for 3 hours. The liquid in the high-pressure reactor was transferred to a stirring kettle, and 12.5 kg of n-propanol was added and stirred for 30 minutes. The liquid after adding n-propanol was transferred to a glass rectification column for vacuum concentration. Part of the solvent was taken out from the top of the column, and a resin dispersion with a content of 22.0 wt% was obtained at the bottom of the column. Among them, in the dispersion, the resin content is 22.0 wt%, the n-propanol content is 43.1 wt%, the ethanol content is 1.0 wt%, and the water content is 33.9 wt%.

[0126] The detection results of the metal ion content of the EW850 perfluorosulfonic acid resin dispersion prepared by the above method and device are shown in Table 8.

[0127] Detection Results of Metal Ion Content in the Dispersion Obtained in Comparative Example 6

[0128]

[0129] It can be seen from Comparative Examples 5-6 that although a quartz glass sleeve was placed in the kettle to avoid the contact between the resin and the metal kettle body, compared with Comparative Examples 3-4, the contents of Ni, Cr, and Fe ions in the prepared dispersion were significantly reduced. However, metal components such as the stirring paddle, bottom pipe, and thermometer thermocouple sleeve in the kettle were still immersed in the dispersion, and there was still metal ion pollution caused by the corrosion of the metal material. Compared with Examples 1-2, the contents of Ni, Cr, and Fe ions in the prepared dispersion were still significantly higher.

[0130] Above, the embodiments of the present invention have been described by way of example. However, the protection scope of the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc. made by those skilled in the art within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a perfluorosulfonic acid resin dispersion, characterized in that, the method comprises the following steps: 1) Pretreat the perfluorosulfonic acid resin, including pickling and washing with water; 2) Mix the pretreated perfluorosulfonic acid resin and a first solvent under heating and pressure control conditions for resin dispersion; 3) After the resin dispersion is completed, lower the temperature of the liquid material to a certain temperature, add a second solvent and mix, filter, and concentrate to obtain the perfluorosulfonic acid resin dispersion; In step 2), the first solvent is a mixed solvent of an alcohol compound and water; In step 3), the second solvent is an alcohol compound.

2. The method according to claim 1, characterized in that, in step 1), both the pickling and the washing with water are carried out in a stirring kettle made of a non-metallic material or with a non-metallic material lining layer; Preferably, after pickling and / or washing with water, a filtering step is included, and the filtering is carried out in a filter made of a non-metallic material or with a non-metallic material lining layer.

3. The method according to claim 1 or 2, characterized in that, step 2) is carried out in a reaction kettle, the inner wall of the reaction kettle is provided with a layer of high-temperature resistant non-metallic material lining layer, and the stirring paddle, thermometer thermocouple sleeve or bottom inserting pipe in the reaction kettle are all made of high-temperature resistant non-metallic materials.

4. The method according to any one of claims 1-3, characterized in that, in step 2), the heating temperature is not lower than 200 °C; Preferably, the pressure of the reaction system in step 2) is 1.0 MPa(g)-8.0 MPa(g).

5. The method according to any one of claims 1-4, characterized in that, in step 3), the addition of the second solvent and mixing are carried out in a stirring kettle made of a non-metallic material or with a non-metallic material lining layer; Preferably, the filtering is carried out in a filter made of a non-metallic material or with a non-metallic material lining layer.

6. The method according to any one of claims 1-5, characterized in that, in step 3), the concentration is carried out in a distillation column, and the material of the distillation column is a non-metallic material or with a non-metallic material lining layer.

7. The method according to claim 6, characterized in that, each device is connected by a pipeline, and the pipeline is made of a non-metallic material or with a non-metallic material lining layer.

8. A device for implementing the method according to any one of claims 1-7, characterized in that, the device includes at least one set of stirring kettle, reaction kettle, stirring kettle and distillation column; Wherein, the at least one set of stirring kettle is used for the pretreatment of the perfluorosulfonic acid resin; The reaction kettle is used for mixing the perfluorosulfonic acid resin and the first solvent under heating and pressure control conditions for resin dispersion; The stirring kettle located after the reaction kettle is used for supplementing the second solvent; the distillation column is used for concentration.

9. The device according to claim 8, characterized in that, the reaction kettle is connected to the stirring kettle for supplementing the second solvent by a pipeline, and the stirring kettle for supplementing the second solvent is connected to the distillation column through a pipeline and a filter, and the pipeline and the filter are both made of a non-metallic material or with a non-metallic material lining layer.

10. The device according to claim 8 or 9, characterized in that, The inner wall of the reactor is provided with a high-temperature resistant non-metallic material lining layer, and the stirring paddle, thermometer thermocouple sleeve and dip tube in the reactor are all made of high-temperature resistant non-metallic materials; Preferably, the reactor body is made of stainless steel. Preferably, the reactor is connected to the distillation column; or the stirring kettle is connected to the distillation column; Preferably, the material of the distillation column is a non-metallic material or has a non-metallic material lining layer.

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